SiriusPoint (SPNT) 10-Q 10 May 21 2021 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2021	May 06, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-36052
Entity Registrant Name	SIRIUSPOINT LTD.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1039994
Entity Address, Address Line One	Point House
Entity Address, Address Line Two	3 Waterloo Lane
Entity Address, City or Town	Pembroke
Entity Address, Postal Zip Code	HM 08
Entity Address, Country	BM
City Area Code	441
Local Phone Number	542-3300
Title of 12(b) Security	Common Shares, $0.10 par value
Trading Symbol	SPNT
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		161,590,077
Entity Central Index Key	0001576018
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Assets
Investments in related party investment funds, at fair value (cost - $891.9; 2020 - $891.9)	$ 1,208.8	$ 1,055.6
Debt securities, trading, at fair value (cost - $2,903.5; 2020 - $91.4)	2,940.3	101.3
Equity securities, trading, at fair value (cost - $5.8; 2020 - N/A)	5.9	0
Other long-term investments, at fair value (cost - $432.8; 2020 - $4.0)	473.1	4
Total investments	4,628.1	1,160.9
Cash and cash equivalents	932.4	526
Restricted cash and cash equivalents	1,411.3	1,187.9
Due from brokers	37.8	94.9
Interest and dividends receivable	10.3	0.9
Insurance and reinsurance balances receivable, net	1,613.8	441.9
Deferred acquisition costs, net and value of business acquired	218.8	68.6
Unearned premiums ceded	247.7	20.5
Loss and loss adjustment expenses recoverable, net	492.6	14.4
Deferred tax asset	256.5	0.4
Intangible assets	174.2	0
Other assets	146.2	18.8
Total assets	10,169.7	3,535.2
Liabilities
Loss and loss adjustment expense reserves	4,259.3	1,310.1
Unearned premium reserves	1,244.8	284.8
Reinsurance balances payable	528.8	78.1
Deposit liabilities	150.7	153
Securities sold, not yet purchased, at fair value	9.2	12
Due to brokers	26.2	0
Accounts payable, accrued expenses and other liabilities	154.4	17.6
Deferred tax liability	223	0
Liability-classified capital instruments	135	0
Debt	829	114.3
Total liabilities	7,560.4	1,969.9
Commitments and contingent liabilities
Shareholders’ equity
Common shares (issued and outstanding: 161,891,354; 2020 - 95,582,733)	16.2	9.6
Additional paid-in capital	1,639.6	933.9
Retained earnings	751.3	620.4
Accumulated other comprehensive income	0.4	0
Shareholders’ equity attributable to SiriusPoint shareholders	2,607.5	1,563.9
Noncontrolling interests	1.8	1.4
Total shareholders' equity	2,609.3	1,565.3
Total liabilities, noncontrolling interests and shareholders’ equity	10,169.7	3,535.2
Series B preference shares
Shareholders’ equity
Preference shares	$ 200	$ 0

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments in related party investment funds, cost	$ 891.9	$ 891.9
Debt securities, trading, cost	2,903.5	91.4
Equity securities, trading, cost	5.8
Other long-term investments, cost	$ 432.8	$ 4
Common share, shares issued (in shares)	161,891,354	95,582,733
Common share, shares outstanding (in shares)	161,891,354	95,582,733
Series B preference shares
Preference shares, par value (in dollars per share)	$ 0.10	$ 0.10
Preference shares, shares authorized (in shares)	8,000,000	8,000,000
Preference shares, shares issued (in shares)	8,000,000	8,000,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues
Net premiums earned	$ 256	$ 146.3
Net realized and unrealized investment gains	31.5	11.6
Net investment income (loss) from investments in related party investment funds	153.2	(200.8)
Other net investment income	1.8	4.2
Net investment income (loss)	186.5	(185)
Other revenues	8.6	0
Total revenues	451.1	(38.7)
Expenses
Loss and loss adjustment expenses incurred, net	148.1	87.8
Acquisition costs, net	69	49.3
Other underwriting expenses	30.2	7.2
Net corporate and other expenses	68.3	6.4
Intangible asset amortization	0.8	0
Interest expense	4.9	2
Foreign exchange gains	(12.4)	(8.2)
Total expenses	308.9	144.5
Income before income tax (expense) benefit	142.2	(183.2)
Income tax expense	(9.8)	(0.4)
Net income (loss)	132.4	(183.6)
Net (income) loss attributable to noncontrolling interests	0	0
Net income (loss) available to SiriusPoint	132.4	(183.6)
Dividends on Series B preference shares	(1.5)	0
Net income allocated to SiriusPoint participating common shareholders	130.9	(183.6)
Net income (loss) available to SiriusPoint common shareholders	$ 130.9	$ (183.6)
Earnings (loss) per share available to SiriusPoint common shareholders
Basic earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ 1.07	$ (1.99)
Diluted earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ 1.05	$ (1.99)
Weighted average number of common shares used in the determination of earnings (loss) per share
Basic (in shares)	116,760,760	92,191,837
Diluted (in shares)	118,146,341	92,191,837

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 132.4	$ (183.6)
Other comprehensive income
Change in foreign currency translation, net of tax	0.4	0
Total other comprehensive income	0.4	0
Comprehensive income (loss)	132.8	(183.6)
Net (income) loss attributable to noncontrolling interests	0	0
Comprehensive income (loss) available to SiriusPoint	$ 132.8	$ (183.6)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Parent	Preference sharesSeries B preference shares	Common shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income	Noncontrolling interests
Balance, beginning of period at Dec. 31, 2019			$ 0	$ 9.4	$ 927.7	$ 476.9	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preference shares, net			0
Issuance of common shares, net				0.1	(0.4)
Issuance of common shares for Sirius Group acquisition				0	0
Issuance of common shares to related party				0	0
Share compensation expense					1.6
Net income (loss)	$ (183.6)					(183.6)
Dividends on preference shares						0
Net change in foreign currency translation	0						0
Balance, end of period at Mar. 31, 2020	1,231.7	$ 1,231.7	0	9.5	928.9	293.3	0	$ 0
Balance, beginning of period at Dec. 31, 2020	1,565.3		0	9.6	933.9	620.4	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preference shares, net			200
Issuance of common shares, net				0.2	65.7
Issuance of common shares for Sirius Group acquisition				5.8	589.7
Issuance of common shares to related party				0.6	48
Share compensation expense					2.3
Net income (loss)	132.4					132.4
Dividends on preference shares						(1.5)
Net change in foreign currency translation	0.4						0.4
Balance, end of period at Mar. 31, 2021	$ 2,609.3	$ 2,607.5	$ 200	$ 16.2	$ 1,639.6	$ 751.3	$ 0.4	$ 1.8

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net income (loss)	$ 132.4	$ (183.6)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Share compensation expense	2.3	1.6
Net interest expense on deposit liabilities	0.8	1
Net realized and unrealized gain on investments and derivatives	(31.8)	(18.7)
Net realized and unrealized (gain) loss on investment in related party investment funds	(153.2)	200.8
Net foreign exchange gains	(12.4)	(8.2)
Gain on bargain purchase	(8.6)	0
Amortization of premium and accretion of discount, net	2	0.1
Amortization of intangible assets	0.8	0
Depreciation and other amortization	1.5	0
Changes in assets and liabilities:
Insurance and reinsurance balances receivable	29	24.7
Deferred acquisition costs, net and value of business acquired	(2.3)	13.2
Unearned premiums ceded	(38.2)	0.7
Loss and loss adjustment expenses recoverable	(17.5)	(1.3)
Deferred tax asset/liability	5	0.4
Other assets	20.1	(1.7)
Interest and dividends receivable, net	(1.4)	(1.6)
Loss and loss adjustment expense reserves	19.1	6.3
Unearned premium reserves	60	(23.9)
Reinsurance balances payable	62.7	(1.2)
Accounts payable, accrued expenses and other liabilities	(119.1)	(11.8)
Net cash provided by (used in) operating activities	(48.8)	(3.2)
Investing activities
Purchases of investments	(316.3)	(241.6)
Proceeds from sales and maturities of investments	233.3	22.3
Purchases of investments to cover short sales	(11.8)	(5.7)
Proceeds from short sales of investments	11.2	53
Change in due to/from brokers, net	75.7	(54.8)
Acquisition of Sirius Group, net (cash and restricted cash acquired of $740.3)	631.9	0
Net cash provided by (used in) investing activities	624	(226.8)
Financing activities
Proceeds from issuance of SiriusPoint common shares, net of costs	57.8	0
Taxes paid on withholding shares	(0.3)	(0.3)
Net payments on deposit liability contracts	(3)	(2.8)
Change in total noncontrolling interests, net	0.1	0
Net cash provided by (used in) financing activities	54.6	(3.1)
Net increase (decrease) in cash, cash equivalents and restricted cash	629.8	(233.1)
Cash, cash equivalents and restricted cash at beginning of period	1,713.9	1,654
Cash, cash equivalents and restricted cash at end of period	$ 2,343.7	$ 1,420.9

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Statement of Cash Flows [Abstract]
Cash and restricted cash acquired	$ 740.3

Organization

Organization	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization On February 26, 2021, the Company complete d the acquisition of Sirius International Insurance Group, Ltd. (“Sirius” or “Sirius Group”) and changed its name from Third Point Reinsurance Ltd. to SiriusPoint Ltd. (“SiriusPoint”). All references to SiriusPoint throughout this Form 10-Q refer to legacy Third Point Reinsurance Ltd., unless otherwise indicated. The results of operations and cash flows of Sirius Group are included from the acquisition date of February 26, 2021 forward. For additional information, see Note 3 to our condensed consolidated financial statements. SiriusPoint Ltd. (together with its consolidated subsidiaries, “SiriusPoint” or the “Company”) was incorporated under the laws of Bermuda on October 6, 2011. Through its subsidiaries, the Company is a provider of global multi-line reinsurance and insurance products. These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 in Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete annual financial statements. In addition, the year-end balance sheet data was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report should be read in conjunction with the audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (the “2020 Form 10-K”), as filed with the U.S. Securities and Exchange Commission on February 23, 2021. In the opinion of management, these unaudited condensed consolidated financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for a fair statement of the Company’s financial position and results of operations as at the end of and for the periods presented. All significant intercompany accounts and transactions have been eliminated. Effective January 1, 2021, the Company changed its reportable segments to: Accident & Health (“A&H”), Specialty, Property, and Runoff & Other. This reflects our larger and expanded operations subsequent to the acquisition of Sirius Group. The change in reportable segments had no impact on the Company’s historical consolidated financial positions, results of operations or cash flows as previously reported. Where applicable, all prior periods presented have been revised to conform to this new presentation. The results for the three months ended March 31, 2021 are not necessarily indicative of the results expected for the full calendar year. Tabular amounts are in U.S. Dollars in millions, except share amounts, unless otherwise noted.

Significant accounting policies

Significant accounting policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Significant accounting policies	2. Significant accounting policies Other than described below, there have been no material changes to the Company’s significant accounting policies as described in its 2020 Form 10-K. Written premium recognition Effective January 1, 2021, the Company changed its accounting policy for assumed written premium recognition. Previously, the Company estimated ultimate premium written for the entire contract period and recorded this estimate at inception of the contract. For contracts where the full premium written was not estimable at inception, the Company recorded premium written for the portion of the contract period for which the amount was estimable. The Company changed its accounting policy to recognize premiums written ratably over the term of the related policy or reinsurance treaty consistent with the timing of when the ceding company has recognized the written premiums. Premiums written include amounts reported by brokers and ceding companies, supplemented by the Company's own estimates of premiums where reports have not been received. The determination of premium estimates requires a review of the Company's experience with the ceding companies, managing general underwriters, familiarity with each market, the timing of the reported information, an analysis and understanding of the characteristics of each class of business and management's judgment of the impact of various factors, including premium or loss trends, on the volume of business written and ceded to the Company. On an ongoing basis, the Company's underwriters review the amounts reported by these third parties for reasonableness based on their experience and knowledge of the subject class of business, taking into account the Company's historical experience with the brokers or ceding companies. The change in policy has been made because it is management’s opinion that the revised policy reflects the timing of when premiums are written by the cedent and reduces uncertainty regarding the assets and liabilities recorded. The following tables provide a summary of the retrospective impact from the change in accounting policy on the Company’s condensed consolidated financial statements: Condensed consolidated balance sheet December 31, 2020 As previously reported Adjustment As adjusted Insurance and reinsurance balances receivable, net $ 559.4 $ (117.5) $ 441.9 Deferred acquisition costs, net and value of business acquired 134.3 (65.7) 68.6 Unearned premiums ceded 27.7 (7.2) 20.5 Total assets 3,725.6 (190.4) 3,535.2 Reinsurance balances payable 80.4 (2.3) 78.1 Unearned premium reserves 472.9 (188.1) 284.8 Total liabilities 2,160.3 (190.4) 1,969.9 Shareholders’ equity attributable to SiriusPoint common shareholders $ 1,563.9 $ — $ 1,563.9 Condensed consolidated statement of income (loss) Three months ended March 31, 2020 As previously reported Adjustment As adjusted Gross premiums written $ 204.1 $ (78.4) $ 125.7 Gross premiums ceded 0.3 (2.8) (2.5) Net premiums written 204.4 (81.2) 123.2 Change in net unearned premium reserves (58.1) 81.2 23.1 Net premiums earned $ 146.3 $ — $ 146.3 Net loss attributable to SiriusPoint common shareholders $ (183.6) $ — $ (183.6) Condensed consolidated statement of cash flows Three months ended March 31, 2020 As previously reported Adjustment As adjusted Insurance and reinsurance balances receivable $ (28.2) $ 52.9 $ 24.7 Deferred acquisition costs, net and value of business acquired (13.8) 27.0 13.2 Unearned premiums ceded 3.5 (2.8) 0.7 Unearned premium reserves 54.5 (78.4) (23.9) Reinsurance balances payable (2.5) 1.3 (1.2) Net cash used in operating activities $ (3.2) $ — $ (3.2) The change in accounting policy had no impact on the previously reported net income (loss) or shareholders’ equity attributable to SiriusPoint common shareholders. While not part of the change in written premium accounting policy described above, premiums earned also include service fee revenue from the Company’s managing general underwriting (“MGU”) subsidiaries. Business combinations and intangible assets The Company accounts for business combinations in accordance with Accounting Standards Codification ("ASC") Topic 805 Business Combinations , and intangible assets that arise from business combinations in accordance with ASC Topic 350 Intangibles – Goodwill and Other . The difference between the fair value of net assets acquired and the purchase price is recorded as a bargain purchase gain in other revenues in the condensed consolidated statements of income (loss). Intangible assets arising from our business acquisitions are classified as either finite or indefinite-lived intangible assets. Finite-lived intangible assets are amortized over their useful lives with the amortization expense being recognized in the condensed consolidated statements of income (loss). The amortization periods approximate the period over which the Company expects to generate future net cash inflows from the use of these assets. All of these assets are subject to impairment testing for the impairment or disposal of long-lived assets when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows. Indefinite-lived intangible assets are however not subject to amortization. The carrying values of intangible assets are reviewed for indicators of impairment at least annually. The Company initially evaluates indefinite-lived intangible assets using a qualitative approach to determine whether it is more likely than not that the fair value is greater than its carrying value. If the results of the qualitative evaluation indicate that it is more likely than not that the carrying value exceeds its fair value, the Company performs the quantitative test for impairment. If indefinite-lived intangible assets are impaired, such assets are written down to their fair values with the related expense recognized in the condensed consolidated statements of income (loss). Liability-classified capital instruments As part of the consideration transferred in the acquisition of Sirius Group, the Company issued various instruments that were classified as liabilities based on their terms, notably the settlement features for each and any potential adjustments to the exercise price for the warrants issued. Liability-classified capital instruments reported in the condensed consolidated balance sheets include Series A preference shares, Merger warrants, Private warrants, Upside rights and Contingent value rights. See Note 3 for additional information on each of these instruments. Defined benefit plans Certain SiriusPoint employees in Europe participate in defined benefit plans. The liability for the defined benefit plans that is reported on the condensed consolidated balance sheets is the current value of the defined benefit obligation at the end of the period, reduced by the fair value of the plan's assets, with adjustments for actuarial gains and losses. The defined benefit pension plan obligation is calculated annually by independent actuaries. The current value of the defined benefit obligation is determined through discounting of expected future cash flows, using interest rates determined by current market interest rates. The service costs and actuarial gains and losses on the defined benefit obligation and the fair value on the plan assets are recognized in the condensed consolidated statements of income (loss). Deferred software costs The Company capitalizes costs related to computer software developed for internal use during the application development stage of software development projects. These costs generally consist of certain external, payroll, and payroll-related costs. The Company begins amortization of these costs once the project is completed and ready for its intended use. Amortization is on a straight-line basis and over a useful life of three Loan participations Loan participations that qualify for sale accounting under the ASC Topic 860 Transfers and Servicing of Financial Assets , are carried at fair value. The fair value of loan participations is estimated using discounted cash flow analysis. The Company includes loan participations in other assets in the condensed consolidated balance sheets. Foreign currency exchange The U.S. dollar is the functional curre ncy for the Company’s businesses except for the Canadian reinsurance operations of Sirius America Insurance Company. T he Company invests in securities denominated in foreign currencies. Assets and liabilities recorded in these foreign currencies are translated into U.S. dollars at exchange rates in effect at the balance sheet date, and revenues and expenses are converted using the average exchange rates for the period. Net foreign exchange gains and losses arising from the translation of functional currencies are reported in shareholder's equity, in accumulated other comprehensive (loss). As of March 31, 2021, the Company had net unrealized foreign currency translation gains of $0.4 million recorded in accumulated other comprehensive income (loss) on its condensed consolidated balance sheet. Assets and liabilities relating to foreign operations are remeasured into the functional currency using current exchange rates; revenues and expenses are remeasured into the functional currency using the weighted average exchange rate for the period. The resulting exchange gains and losses are reported as a component of net income in the period in which they arise within net realized and unrealized gains (losses) and net foreign exchange gains (losses). Reclassifications Certain amounts in the prior period financial statements have been reclassified to conform to the presentation of the current period financial statements. These reclassifications had no impact on the previously reported net income (loss) or shareholders’ equity attributable to SiriusPoint common shareholders. Recently issued accounting standards Issued and effective as of March 31, 2021 In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The amendments in ASU 2019-12 simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. A SU 2019-12 is effective for public business entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years . The Company has fully adopted all provisions of the guidance with consideration of the various transition methods. The Company also adopted all other provisions in the guidance, including the requirement for an entity to recognize a franchise tax (or similar tax) that is partially based on income as an income-based tax and account for any incremental amount incurred as a non-income-based tax through a cumulative-effect adjustment to retained earnings. These provisions did not have a material impact on the Company’s condensed consolidated financial statements or were not applicable to the Company. In January 2020, the FASB issued Accounting Standards Update 2020-01, Investments—Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 (a consensus of the Emerging Issues Task Force) (“ASU 2020-01”). The amendments in ASU 2020-01 clarify certain interactions between the guidance to account for certain equity securities under Topic 321, the guidance to account for investments under the equity method of accounting in Topic 323, and the guidance in Topic 815, which could change how an entity accounts for an equity security under the m easurement alternative for a forward contract or purchased option to purchase securities that, upon settlement of the forward contract or exercise of the purchased option, would be accounted for under the equity method of accounting or the fair value option in accordance with Topic 825, Financial Instruments. These amendments improve current U.S. GAAP by reducing diversity in practice and increasing comparability of the accounting for these interactions. ASU 2020-01 is effective for public business entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Adoption of ASU 2020-01 did not have a material impact on the Company’s condensed consolidated financial statements. In October 2020, the FASB issued Accounting Standards Update 2020-09, Debt (Topic 470): Amendments to SEC Paragraphs Pursuant to SEC Release No. 33-10762 (“ASU 2020-09”). The amendments in ASU 2020-09 amend and supersede SEC paragraphs in the Accounting Standards Codification to reflect the issuance of SEC Release No. 33-10762 related to financial disclosure requirements for subsidiary issuers and guarantors of registered debt securities and affiliates whose securities are pledged as collateral for registered securities. SEC Release No. 33-10762 simplifies the disclosure requirements related to certain registered securities under Rules 3-10 and 3-16 of Regulation S-X, permitting registrants to provide certain alternative financial disclosures and non-financial disclosures in lieu of separate consolidating financial statements for subsidiary issuers and guarantors of registered debt securities if certain conditions are met. The amendments in ASU 2020-09 are generally effective for filings on or after January 4, 2021, with early application permitted. The Company adopted the new disclosure requirements permitted under ASU 2020-09 effective for the quarter ended March 31, 2021. Issued but not yet effective as of March 31, 2021 Other accounting pronouncements issued during the three months ended March 31, 2021 were either not relevant to the Company or did not impact the Company’s condensed consolidated financial statements.

Acquisition of Sirius Group

Acquisition of Sirius Group	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Acquisition of Sirius Group	3. Acquisition of Sirius Group Overview On February 26, 2021, the Company completed its acquisition of Sirius Group. Prior to the closing of the acquisition of Sirius Group, Sirius Group was a publicly listed company and traded on the Nasdaq Global Select Market under the symbol “SG”. Sirius Group, through its wholly owned subsidiaries, provides multi-line insurance and reinsurance on a worldwide basis. The acquisition of Sirius Group is expected to benefit the Company through expanded underwriting capabilities, geographic footprint and product offerings. Pursuant to the terms of the acquisition, each common share, par value $0.01 per share, of Sirius Group (each, a “Sirius Share”) that was issued and outstanding immediately prior to the closing date of the acquisition was canceled and converted into the right to receive one of the following three consideration options at the shareholder’s election: • $9.50 in cash; • a combination of common shares, par value $0.10 per share, of the Company (“Company shares”), and CVR consideration comprising (1) 0.743 of a Company share and (2) one contractual contingent value right (each, a “CVR”), which represents the right to receive a contingent cash payment, which, taken together with the fraction of the Company share received, guarantee that on the second anniversary of the acquisition, the electing shareholder will have received equity and cash valued at least $13.73 per Sirius Share; should SiriusPoint shares trade at or above $18.50 over any 14 consecutive trading day period up to the second anniversary of the acquisition, the CVR component will be automatically extinguished (4.7 million CVRs were issued under this consideration option); or • a combination of cash, Company shares, Series A preference shares, warrants and Upside Rights (a “Mixed Election”) comprising (1) $0.905 in cash, (2) 0.496 Company shares, (3) 0.106 Series A preference shares, par value $0.10 per share, of the Company (the “Series A Preference Shares”), (4) 0.190 of a warrant (each, a “Merger warrant”) and (5) $0.905 aggregate principal amount of an “upside right” issued by the Company (collectively, the “Upside Rights”). Pursuant to the Company Voting and Support Agreement, CM Bermuda Limited (“CM Bermuda”), whose parent company is CMIG International Holdings Pte. Ltd. (“CMIG International”), made the Mixed Election. The aggregate consideration for the transaction included the issuance of 58,331,196 SiriusPoint common shares valued at $595.6 million and $100.4 million of cash. In addition to the SiriusPoint common shares and the cash, the aggregate consideration for the transaction also consisted of the issuance of preference shares, warrants, and other contingent value components, as discussed below. The cash consideration portion was funded from available cash resources and $48.6 million from the issuance of SiriusPoint common shares pursuant to the equity commitment letter between the Company, Third Point Opportunities Master Fund Ltd. and Daniel S. Loeb, pursuant to which Third Point Opportunities Master Fund Ltd. committed to purchase up to 9.5% of the Company’s shares in connection with closing of the acquisition of Sirius Group. Series A Preference Shares On February 26, 2021, certain holders of Sirius Group shares elected to receive Series A preference shares with respect to the consideration price of the Sirius Group acquisition. The Company issued 11,720,987 of designated Series A preference shares, with a par value of $0.10 per share. The Series A preference shares rank pari passu with the Company’s common shares with respect to the payment of dividends or distributions. Each Series A preference share has voting power equal to the number of Company shares into which it is convertible, and the Series A preference shares and Company shares shall vote together as a single class with respect to any and all matters. During the three months ended March 31, 2021, the Company did not declare or pay dividends to Series A preference shareholders. Upon the third anniversary of the closing date of the Sirius Group acquisition, as described in the Series A Certificate of Designation and pursuant to the analysis of an independent actuarial team, the Company will calculate the total amount of TPRE’s COVID-19 losses in excess of $51.1 million (the “TPRE Net COVID Loss”) and the total amount of Sirius Group’s COVID-19 losses in excess of $150.0 million (the “Sirius Net COVID Loss”). If TPRE’s COVID-19 losses are less than or equal to $51.1 million, the TPRE Net COVID Loss will equal $0, and if Sirius Group’s COVID-19 losses are less than or equal to $150.0 million, the Sirius Net COVID Loss will equal $0. Should the Sirius Net COVID Loss be greater than the TPRE Net COVID Loss, then a number of Series A preference shares will be forfeited equal to (x) the lesser of (i) the Sirius Net COVID Loss minus the TPRE Net COVID Loss and (ii) $100.0 million divided by (y) the volume weighted average price (“VWAP”) measured over the 30 business day (where normal trading occurs on U.S. national and regional exchanges) (“Trading Day”) period prior to the date five business days after the calculation of the TPRE Net COVID Loss and Sirius Net COVID Loss (the “Final Adjustment Determination Date”). Should the TPRE Net COVID Loss be greater than the Sirius Net COVID Loss, then a number of Series A preference shares will be issued equal to (x) the TPRE Net COVID Loss minus the Sirius Net COVID Loss divided by (y) the 30-Trading Day VWAP during the period prior to the Final Adjustment Determination Date. After either such adjustment occurs, the Series A preference shares will convert into common shares based on the conversion ratio of one Series A preference share to one common share, subject to the adjustment as set forth in the Series A Certificate of Designation. Series A preference shares are recorded at fair value in the liability-classified capital instruments line of the condensed consolidated balance sheets. Merger Warrants On February 26, 2021, the Company entered into a warrant agreement (the “Warrant Agreement”) with respect to the consideration price of the Sirius Group acquisition . Pursuant to the Warrant Agreement, each warrant (“Merger warrant”) permits the holder thereof to purchase one common share for $11.00, subject to adjustment as set forth in the Warrant Agreement. The warrants are exercisable at any time after February 26, 2021 through the fifth anniversary. If the warrants are not exercised prior to the fifth anniversary of the closing date of the acquisition of Sirius Group, the warrants will expire without value. As of March 31, 2021, the Company had reserved for issuance common shares underlying warrants to purchase, in the aggregate, up to 21,009,324 common shares, to previous Sirius Group common shareholders. The Merger warrants are recorded at fair value in the liability-classified capital instruments line of the condensed consolidated balance sheets. Sirius Group Private Warrants On February 26, 2021, the Company entered into an assumption agreement (the “Assumption Agreement”) by and among (i) the Company, (ii) Bain Capital Special Situations Asia, L.P., a Cayman Islands limited partnership (“Bain”), (iii) CCOF Master, L.P., a Delaware limited partnership (“Carlyle”), (iv) Centerbridge Credit Partners Master, LP, a Delaware limited partnership, and Centerbridge Special Credit Partners III, LP, a Delaware limited partnership (collectively, “Centerbridge”), and (v) GPC Partners Investments (Canis) LP, a Delaware limited partnership (“Gallatin” and, together with Bain, Carlyle and Centerbridge, collectively, the “Sirius Warrant Holders”). Pursuant to the terms of the Assumption Agreement, the Company agreed to assume all of the warrants issued on November 5, 2018 and November 28, 2018 (the “Private warrants”) by Sirius Group to the Sirius Warrant Holders. Prior to February 26, 2021, the Sirius Warrants were exercisable for an aggregate of 5,418,434 Sirius Group shares. On February 26, 2021, each Sirius Warrant ceased to represent the right to purchase Sirius Group shares and each Sirius Warrant Holder was instead granted the right to receive, upon exercise of a Private warrant, a contingent cash payment which, taken together with the fraction of the Company common share received, guarantees that on the second anniversary of February 26, 2021, the electing shareholder will have received equity and cash valued at least $13.73 per Sirius Group common share. The exercise price was also adjusted in accordance with the terms of the merger and the Sirius Warrants to $13.00. The Private warrants are recorded at fair value in the liability-classified capital instruments line of the condensed consolidated balance sheets. Sirius Group Public Warrants Under the merger agreement between Sirius Group and Easterly Acquisition Corporation, each of Easterly’s existing issued and outstanding public warrants was converted into a warrant exercisable for Sirius Group common shares (“Sirius Group Public Warrants”). From February 26, 2021, holders of the Sirius Group Public Warrants have the right to receive the merger consideration that the holder of the Sirius Group Public Warrants would have received if such holder had exercised his, her or its warrants immediately prior to February 26, 2021. Because the exercise price of such Sirius Group Public Warrants of $18.89 was greater than the per share merger consideration, no such warrants were exercised prior to the completion of the merger and therefore no merger consideration was paid to holders of such warrants. The Sirius Group Public Warrants are no longer listed on any public exchange and will terminate in accordance with their terms. The fair value of the Sirius Group Public Warrants is estimated to be zero. Upside Rights On February 26, 2021, the Company issued Upside Rights with respect to the consideration price of the Sirius Group acquisition. Pursuant to the Upside Rights, if (i) the last reported sales price of the Company’s common shares for each of 30 consecutive trading days exceeds the target price of $20.00 (the “Target Price”), subject to adjustment, prior to the first anniversary of February 26, 2021, or (ii) the Company enters into a definitive agreement to consummate a change of control transaction and the per share consideration in such transaction exceeds the Target Price, the principal amount of the Upside Rights will become immediately due and payable. Settlement of the Upside Rights will be in a number of Company common shares equal to $100,070,726 divided by the Company’s average share price determined using a 30-day VWAP, or in the case of a change of control transaction, the lesser of the per share consideration being offered in such change of control transaction and the Company’s average share price determined using a 30-day VWAP. The Upside Rights are recorded at fair value in the liability-classified capital instruments line of the condensed consolidated balance sheets. Contingent Value Rights On February 26, 2021, the Company entered into a contingent value rights agreement (the “CVR Agreement”) with respect to the consideration price of the Sirius Group acquisition. Pursuant to the CVR Agreement, the Company issued CVRs representing the right to receive a contingent cash payment of (1) in the case of acceleration upon certain breaches of the CVR Agreement, $13.73 minus the volume weighted average price of the Company shares measured over the 14 consecutive trading day period beginning on the date a breach is declared, multiplied by 0.743, (2) on the second anniversary (the “Maturity Date”) of the merger, $13.73 minus the volume weighted average price of the Company’s common shares measured over the 14 consecutive trading day period prior to the Maturity Date multiplied by 0.743 and (3) in the case of redemption by the Company prior to the Maturity Date, the discounted present value of $13.73, discounted from the Maturity Date to the last day of the 14 consecutive trading day period beginning on the date of the redemption notice (“Redemption Valuation Period”), minus the volume weighted average price of the Company shares measured over the Redemption Valuation Period multiplied by 0.743. The CVRs are recorded at fair value in the liability-classified capital instruments line of the condensed consolidated balance sheets. Purchase Price The components of the Company's total purchase price for Sirius Group at February 26, 2021 were as follows: Cash consideration Sirius Group shares acquired for cash $ 100.4 Common Shares Common Shares issued by SiriusPoint 58,331,196 SiriusPoint share price as of February 26, 2021 $ 10.21 595.6 Preference Shares Series A Preference Shares issued, at fair value 40.8 Series B Preference Shares issued, at fair value (1) 200.0 Warrants Merger warrants issued, at fair value 53.4 Private warrants issued, at fair value 7.3 Upside Rights Upside Rights issued, at fair value 6.5 Contingent value rights (CVRs) CVRs issued, at fair value 27.0 CVR waiver restricted shares 0.7 Other Fair value of the replaced Sirius Group equity awards attributable to pre-combination services 37.5 Transaction fee reimbursement 8.0 Total purchase price $ 1,077.2 (1) See Note 16 for additional information. Fair Value of Net Assets Acquired and Liabilities Assumed The following table summarizes the estimated fair values of major classes of identifiable assets acquired and liabilities assumed of Sirius Group as of February 26, 2021, the date the transaction closed: Identifiable net assets: Cash and investments $ 3,944.1 Insurance and reinsurance balances receivable, net 1,201.0 Reinsurance assets 649.7 Value of business acquired 147.9 Deferred tax asset 230.5 Intangible assets 175.0 Other assets 181.9 Loss and loss adjustment expense reserves (2,928.5) Unearned premium reserves (900.0) Deferred tax liability (192.4) Debt (728.2) Other liabilities (695.2) Total identifiable net assets acquired 1,085.8 Total purchase price 1,077.2 Bargain purchase gain $ 8.6 The bargain purchase gain represents the excess of the fair value of the underlying net assets acquired and liabilities assumed over the purchase price. The gain from bargain purchase is included in other revenues in the condensed consolidated statements of income (loss). The bargain purchase determination is consistent with the fact that Sirius Group’s shares traded at a discount to book value and the need for Sirius Group to quickly diversify its ownership base. An explanation of the significant fair value adjustments is as follows: • Goodwill and intangibles - to eliminate the goodwill and intangible assets in Sirius Group net assets acquired as part of the purchase accounting; • Loss and loss adjustment expense reserves - to record loss and loss adjustment expense reserves at fair value, reflecting an increase for a market based risk margin, which represents the cost of capital required by a market participant to assume the loss and loss adjustment expense reserves of Sirius Group, partially offset by a deduction which represents the discount due to the present value calculation of the loss and loss adjustment expense reserves based on the expected payout of the net unpaid loss and loss adjustment expense reserves. In addition, management increased certain casualty loss reserves by $70.0 million in order to reflect a consistent reserving approach between the two companies. The increase was in response to accumulated loss experience and the broader industry trends of social inflation; • Deferred acquisition costs - to eliminate Sirius Group’s deferred acquisition costs asset; • Value of business acquired (“VOBA”) - the expected future losses and expenses associated with the policies that were in-force as of the closing date of the transaction were estimated and compared to the future premium remaining expected to be earned. The difference between the risk-adjusted future loss and expenses, discounted to present value and the unearned premium reserve, was estimated to be the VOBA; • Finite-lived insurance intangible assets - to establish the fair value of identifiable finite-lived insurance intangible assets acquired, including customer and other relationships, trade names and technology. The Company recognized identifiable finite lived intangible assets of $130.0 million, which will be amortized over their estimated useful lives; • Indefinite-lived insurance intangible assets - to establish the fair value of identifiable indefinite-lived insurance intangible assets acquired (Lloyd’s capacity and insurance licenses). The Company recognized identifiable indefinite lived intangible assets of $45.0 million; and • Deferred tax - to reflect adjustments to net deferred tax assets and liabilities related to the fair value adjustments above. Identifiable intangible assets at February 26, 2021 and at March 31, 2021 , consisted of the following, and are included in intangible assets on the Company’s condensed consolidated balance sheet: Amount Economic Useful Life Distribution relationships $ 75.0 17 years MGA relationships 34.0 13 years Lloyd’s Capacity - Syndicate 1945 38.0 Indefinite Insurance licenses 7.0 Indefinite Trade name 16.0 16 years Internally developed and used computer software 5.0 5 years Identifiable intangible assets, before amortization, at February 26, 2021 175.0 Amortization (from February 26, 2021 through March 31, 2021) (0.8) Net identifiable intangible assets at March 31, 2021 related to the acquisition of Sirius Group $ 174.2 An explanation of the identifiable intangible assets is as follows: • Distribution relationships - refers to the relationships Sirius Group has established with external independent distributors and brokers to facilitate the distribution of its products in the marketplace. As a result of owning the distribution relationships, management will not have to duplicate historical marketing, training, and start-up expenses to redevelop comparable relationships to support business operations; • MGA relationships - refers to relationships with managing general agents on the direct insurance business. Through the MGA relationships, Sirius Group generates a predictable and recurring stream of service fee revenue; • Lloyd’s Capacity - Syndicate 1945 - relates to relationships associated with the right to distribute and market policies underwritten through Lloyd’s Syndicate 1945; • Insurance licenses - Sirius Group, like other insurance providers, is required to maintain licenses to produce and service insurance contracts. Insurance licenses are estimated to have an indefinite life and are therefore not amortized but will be subject to periodic impairment testing; • Trade name - represents the value of the Sirius Group brand acquired; and • Internally developed and used computer software - represents the value of internally developed and used computer software to be utilized by the Company. Financial results The following table summarizes the results of Sirius Group since February 26, 2021 that have been included in the Company's condensed consolidated statements of income: For the period from Total revenues $ 146.2 Net income $ 23.3 Supplemental Pro Forma Information Sirius Group’s results have been included in the Company's condensed consolidated financial statements from February 26, 2021 to March 31, 2021. The following table presents unaudited pro forma consolidated financial information for the three months ended March 31, 2021 and 2020 and assumes the acquisition of Sirius Group occurred on January 1, 2020. The unaudited pro forma consolidated financial information is provided for informational purposes only and is not necessarily, and should not be assumed to be, an indication of the results that would have been achieved had the transaction been completed as of January 1, 2020 or that may be achieved in the future. The unaudited pro forma consolidated financial information does not give consideration to the impact of possible revenue enhancements, expense efficiencies, synergies or asset dispositions that may result from the acquisition of Sirius Group. In addition, unaudited pro forma consolidated financial information does not include the effects of costs associated with any restructuring or integration activities resulting from the acquisition of Sirius Group, as such costs cannot be determined at this time. 2021 2020 Total revenues $ 664.7 $ 390.3 Net income (loss) $ 165.8 $ (461.4) Among other adjustments, and in addition to the fair value adjustments and recognition of identifiable intangible assets noted above, other material nonrecurring pro forma adjustments directly attributable to the acquisition of Sirius Group principally included certain adjustments to recognize transaction related costs, align reserving approach, amortize fair value adjustments, amortize identifiable indefinite lived intangible assets and recognize related tax impacts.

Segment reporting

Segment reporting	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment reporting	4. Segment reporting The determination of the Company’s business segments is based on the manner in which management monitors the performance of its operations. The Company reports four operating segments: Accident & Health (“A&H”), Specialty, Property, and Runoff & Other. Non-underwriting income and expenses are presented as a reconciliation to the Company’s income (loss) before income tax expense. The Company does not manage its assets by segment; accordingly, total assets are not allocated to the segments. Accident & Health (“A&H”) A&H consists of the Company’s insurance, reinsurance, and MGUs (which include ArmadaCorp Capital, LLC ("Armada") and International Medical Group, Inc. (“IMG”) that offer accident and health products on a worldwide basis: Accident and Health insurance and reinsurance The Company is an insurer of accident and health insurance business in the United States and internationally, on either an admitted or surplus lines basis, as well as a reinsurer of medical expense, travel and personal accident on a treaty or facultative basis worldwide. The MGU unit writes health insurance business worldwide through IMG and within the United States via Armada. Specialty Specialty consists of the Company’s insurance and reinsurance underwriting units which offer specialty & casualty product lines on a worldwide basis. Specialty lines represent unique risks where the more difficult and unusual risks are underwritten, and much of the market is characterized by a high degree of specialization. The following provides details of Specialty by product line: Aviation & Space Aviation insurance covers loss of or damage to an aircraft and the aircraft operations' liability to passengers, cargo and hull as well as to third parties. Additionally, liability arising out of non-aircraft operations such as hangars, airports and aircraft products can be covered. Space insurance primarily covers loss of or damage to a satellite during launch and in orbit. The book consists of treaty, written on both a proportional and excess of loss basis, facultative, and primary business. Marine & Energy The Company provides marine & energy reinsurance, primarily written on an excess of loss and proportional basis. Coverage offered includes damage to ships and goods in transit, marine liability lines, and offshore energy industry insurance. The Company also writes yacht business, both on reinsurance and a primary basis. The marine & energy portfolio is diversified across many countries and regions. Credit The Company writes credit and bond reinsurance worldwide. The bulk of the business is traditional short-term commercial credit insurance, covering pre-agreed domestic and export sales of goods and services with typical coverage periods of 60 to 120 days. Losses under these policies are correlated to adverse changes in a respective country's gross national product. Contingency The Company’s contingency insurance book covers event cancellation and non-appearance. The Company offers this class on a treaty reinsurance basis on a selective basis for a few key clients. Casualty Casualty represents a cross section of all casualty lines, including general liability, umbrella, auto, workers compensation, professional liability, and other specialty classes, written on a proportional and excess of loss basis. Environmental The Company underwrites a pure environmental insurance book in the U.S. consisting of four core products that revolve around pollution coverage, which are premises pollution liability, contractor's pollution liability, contractor's pollution and professional liability. Mortgage The Company underwrites mortgage risks both as reinsurance and by retrocession. Mortgage insurance is an insurance policy that compensates lenders or investors for losses arising from the default of a mortgage loan. Mortgage insurance can refer to private mortgage insurance, mortgage life insurance or insurance provided under the credit risk sharing transactions from Fannie Mae and Freddie Mac. Property Property consists of the Company’s underwriting lines of business which offer Property Catastrophe Excess Reinsurance, Agriculture Reinsurance and Other Property on a worldwide basis. The following provides details of Property by product line: Property Catastrophe Excess Reinsurance Property catastrophe excess of loss reinsurance treaties cover losses from catastrophic events. The Company writes a worldwide book with the largest concentration of exposure in Europe and the United States. The U.S. book has a national account focus supporting principally the lower and/or middle layers of large capacity programs and also consists of select small regional and standard lines carriers. The exposures written in the international book are diversified across many countries, regions, perils and layers. Agriculture Reinsurance The Company provides stop-loss reinsurance coverage to companies writing U.S. government-sponsored multi-peril crop insurance ("MPCI"). The Company’s participation is net of the government's stop-loss reinsurance protection. The Company also provides coverage for crop-hail and certain named perils when bundled with MPCI business. The Company also writes agriculture business outside of the United States. Other Property The Company participates in the broker market for property reinsurance treaties written on a proportional and excess of loss basis. For the Company’s international business, the book consists of treaty, written on both a proportional and excess of loss basis, facultative, and primary business, primarily in Europe, Asia and Latin America. In the United States, the book predominantly centers on significant participations on proportional and excess of loss treaties mostly in the excess and surplus lines of the market. Runoff & Other Runoff & Other consists of asbestos risks, environmental risks and other long-tailed liability exposures, and results from Sirius Global Solutions Holding Company, including the acquisition and management of runoff liabilities for insurance and reinsurance companies, both in the United States and internationally. Runoff & Other also includes retroactive reinsurance contracts consisting of loss portfolio transfers, adverse development covers and other forms of reserve reinsurance providing indemnification of loss and loss adjustment expense reserves with respect to past loss events. The following is a summary of the Company’s operating segment results for the three months ended March 31, 2021 and 2020: Three months ended March 31, 2021 A&H Specialty Property Runoff & Total Gross premiums written (1) $ 134.8 $ 167.7 $ 62.1 $ 2.0 $ 366.6 Net premiums written (1) 103.6 144.5 60.3 1.9 310.3 Net premiums earned (1) 35.0 139.0 80.2 1.8 256.0 Loss and loss adjustment expenses incurred, net (2) 14.0 87.1 45.4 1.6 148.1 Acquisition costs, net 5.1 42.3 21.2 0.4 69.0 Other underwriting expenses (2) 10.6 9.9 8.2 1.5 30.2 Net underwriting income (loss) $ 5.3 $ (0.3) $ 5.4 $ (1.7) 8.7 Other revenues 8.6 Net investment income 186.5 Net corporate and other expenses (68.3) Intangible asset amortization (0.8) Interest expense (4.9) Foreign exchange gains 12.4 Income before income tax expense $ 142.2 Underwriting Ratios: (3) Loss ratio 40.0 % 62.7 % 56.6 % NM 57.8 % Acquisition cost ratio 14.6 % 30.4 % 26.5 % NM 27.0 % Other underwriting expenses ratio 30.3 % 7.1 % 10.2 % NM 11.8 % Combined ratio (4) 84.9 % 100.2 % 93.3 % NM 96.6 % Three months ended March 31, 2020 A&H Specialty Property Runoff & Total Gross premiums written (1) $ 1.3 $ 79.4 $ 45.0 $ — $ 125.7 Net premiums written (1) 1.3 76.9 45.0 — 123.2 Net premiums earned (1) 1.2 99.4 45.1 0.6 146.3 Loss and loss adjustment expenses incurred, net (2) 1.0 67.4 18.1 1.3 87.8 Acquisition costs, net 0.2 33.5 16.0 (0.4) 49.3 Other underwriting expenses (2) — 4.5 1.5 1.2 7.2 Net underwriting income (loss) $ — $ (6.0) $ 9.5 $ (1.5) 2.0 Net investment loss (185.0) Net corporate and other expenses (6.4) Interest expense (2.0) Foreign exchange gains 8.2 Loss before income tax expense $ (183.2) Underwriting Ratios: (3) Loss ratio 83.3 % 67.8 % 40.1 % NM 60.0 % Acquisition cost ratio 16.7 % 33.7 % 35.5 % NM 33.7 % Other underwriting expenses ratio — % 4.5 % 3.3 % NM 4.9 % Combined ratio (4) 100.0 % 106.0 % 78.9 % NM 98.6 % (1) Includes service fee revenue from the Company’s MGUs of $10.8 million for the three months ended March 31, 2021 (2020 - $nil). (2) Loss and loss adjustment expenses incurred, net and other underwriting expenses include expenses associated with the Company’s MGUs of $1.0 million and $7.3 million, respectively, for the three months ended March 31, 2021 (2020 - $nil). (3) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (4) Ratios considered not meaningful ("NM") to Runoff & Other. (5) The Company modified the presentation of its operating segments in the three months ended March 31, 2021 to better align with the manner in which

Cash, cash equivalents, restric

Cash, cash equivalents, restricted cash and restricted investments	3 Months Ended
	Mar. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash, cash equivalents, restricted cash and restricted investments	5. Cash, cash equivalents, restricted cash and restricted investments The following table provides a summary of cash and cash equivalents, restricted cash and restricted investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Cash and cash equivalents $ 932.4 $ 526.0 Restricted cash securing letter of credit facilities (1) 463.6 306.0 Restricted cash securing reinsurance contracts (2) 929.7 881.9 Restricted cash held by managing general underwriters 18.0 — Total cash, cash equivalents and restricted cash (3) 2,343.7 1,713.9 Restricted investments securing reinsurance contracts (2) 1,084.5 86.4 Total cash, cash equivalents, restricted cash and restricted investments $ 3,428.2 $ 1,800.3 (1) Restricted cash securing letter of credit facilities primarily pertains to letters of credit that have been issued to the Company’s clients in support of our obligations under reinsurance contracts. The Company will not be released from the obligation to provide these letters of credit until the reserves underlying the reinsurance contracts have been settled. The time period for which the Company expects each letter of credit to be in place varies from contract to contract but can last several years. (2) Restricted cash and restricted investments securing reinsurance contracts pertain to trust accounts securing the Company’s contractual obligations under certain reinsurance contracts that the Company will not be released from until the underlying risks have expired or have been settled. Restricted investments include certain investments in debt securities and limited partnership interests in Third Point Enhanced LP. The time period for which the Company expects these trust accounts to be in place varies from contract to contract, but can last several years. (3) Cash, cash equivalents and restricted cash as reported in the Company’s condensed consolidated statements of cash flows.

Investments

Investments	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Investments	6. Investments The Company’s invested assets consist of investment securities and other long-term investments held for general investment purposes. The portfolio of investment securities includes debt securities, equity securities, and other-long term investments which are all classified as trading securities. Realized and unrealized investment gains and losses on trading securities are reported in pre-tax revenues. Debt securities The following tables provide the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses), and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020: March 31, 2021 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 586.0 $ 1.9 $ (0.3) $ 7.0 $ 594.6 Residential mortgage-backed securities 390.9 0.8 (2.3) 2.8 392.2 Commercial mortgage-backed securities 124.1 0.1 (1.2) — 123.0 Corporate debt securities 551.0 4.1 (1.7) 11.2 564.6 U.S. government and government agency (1) 1,127.5 1.7 (2.1) 13.8 1,140.9 Non-U.S. government and government agency 120.3 0.1 — 0.9 121.3 U.S. states, municipalities and political subdivision 0.9 — — — 0.9 Preferred stocks 2.8 — — — 2.8 Total debt securities (2) $ 2,903.5 $ 8.7 $ (7.6) $ 35.7 $ 2,940.3 (1) The Company had $9.2 million of short positions in long duration U.S. Treasuries as of March 31, 2021. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $1,031.5 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of March 31, 2021. December 31, 2020 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 1.2 $ 0.1 $ — $ — $ 1.3 Residential mortgage-backed securities 8.1 0.6 — — 8.7 Bank debt 0.3 0.1 — — 0.4 Corporate debt securities 29.4 8.4 (0.1) — 37.7 U.S. government and government agency (1) 52.4 1.7 (0.9) — 53.2 Total debt securities (2) $ 91.4 $ 10.9 $ (1.0) $ — $ 101.3 (1) The Company had $12.0 million of short positions in long duration U.S. Treasuries as of December 31, 2020. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $50.6 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of December 31, 2020. The weighted average duration of the Company's debt securities as of March 31, 2021 was approximately 1.8 years (December 31, 2020 - 10.5 years). The following table provides the cost or amortized cost and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020 by contractual maturity. Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. March 31, 2021 December 31, 2020 Cost or Fair value Cost or Fair value Due in one year or less $ 1,189.5 $ 1,203.5 $ 50.0 $ 50.6 Due after one year through five years 449.9 460.6 2.8 3.0 Due after five years through ten years 116.5 116.8 — — Due after ten years 43.8 46.8 29.4 37.7 Mortgage-backed and asset-backed securities 1,101.0 1,109.8 9.2 10.0 Preferred stocks 2.8 2.8 — — Total debt securities $ 2,903.5 $ 2,940.3 $ 91.4 $ 101.3 The following table summarizes the ratings and fair value of debt securities held in the Company's investment portfolio as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 AAA $ 804.6 $ 53.2 AA 1,645.7 — A 239.6 9.1 BBB 164.9 37.7 Other 85.5 1.3 Total debt securities (1) $ 2,940.3 $ 101.3 (1) Credit ratings are assigned based on the following hierarchy: 1) Standard & Poor's ("S&P") and 2) Moody's Investors Service. As of March 31, 2021 , the above totals included $44.2 million of sub-prime securities. Of this total, $18.6 million was rated AAA, $13.7 million rated AA and $11.9 million rated A. As of December 31, 2020, the above totals included $8.7 million of A rated sub-prime securities. Equity securities and other long-term investments The cost or amortized cost, gross unrealized investment gains and losses, net foreign currency gains, and fair values of the Company’s equity securities and other long-term investments as of March 31, 2021 and December 31, 2020, were as follows: March 31, 2021 Cost or Gross Gross Net foreign Fair value Equity securities $ 5.8 $ — $ (0.1) $ 0.2 $ 5.9 Other long-term investments $ 432.8 $ 39.8 $ (1.0) $ 1.5 $ 473.1 December 31, 2020 Cost or Gross Gross Net foreign Fair value Other long-term investments $ 4.0 $ — $ — $ — $ 4.0 Equity securities at fair value consisted of the following as of March 31, 2021: March 31, Fixed income mutual funds $ 1.8 Common stocks 4.1 Total equity securities $ 5.9 Other long-term investments at fair value consisted of the following as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Hedge funds and private equity funds (1) $ 242.1 $ — Limited liability companies and private equity securities 231.0 4.0 Total other long-term investments $ 473.1 $ 4.0 (1) Includes $161.9 million of investments valued at NAV and $80.2 million of investments valued at Level 3. Hedge funds and private equity funds The Company holds investments in hedge funds and private equity funds, which are included in other long-term investments. As of March 31, 2021 , the Company held i nvestments in 8 hedge funds and 19 private equity funds. The largest investment in a single fund was $67.9 million as of March 31, 2021. The following table summarizes investments in hedge funds and private equity interests by investment objective and sector as of March 31, 2021: March 31, 2021 Fair value Unfunded Hedge funds Long/short multi-sector $ 29.9 $ — Distressed mortgage credit 67.9 — Private credit 23.4 — Other 1.3 — Total hedge funds 122.5 — Private equity funds Energy infrastructure & services 51.3 25.8 Multi-sector 9.3 6.5 Healthcare 24.5 4.9 Life settlement 13.1 — Manufacturing/Industrial 17.2 — Private equity secondaries 0.6 0.7 Other 3.6 1.3 Total private equity funds 119.6 39.2 Total hedge and private equity funds included in other long-term investments $ 242.1 $ 39.2 Redemption of investments in certain hedge funds is subject to restrictions including lock-up periods where no redemptions or withdrawals are allowed, restrictions on redemption frequency, and advance notice periods for redemptions. Amounts requested for redemptions remain subject to market fluctuations until the redemption effective date, which generally falls at the end of the defined redemption period. The following summarizes the March 31, 2021 fair value of hedge funds subject to restrictions on redemption frequency and advance notice period requirements for investments in active hedge funds: Notice Period Redemption Frequency 1-29 days 30-59 days 60-89 days 90-119 days 120+ days Total Quarterly $ — $ 0.6 $ 29.9 $ 67.9 $ — $ 98.4 Semi-annual — — 0.3 — — 0.3 Annual — — — 0.3 23.5 23.8 Total $ — $ 0.6 $ 30.2 $ 68.2 $ 23.5 $ 122.5 Certain of the hedge fund and private equity fund investments in which the Company is invested are no longer active and are in the process of disposing of their underlying investments. Distributions from such funds are remitted to investors as the fund's underlying investments are liquidated. As of March 31, 2021, no dis tributions were outstanding from these investments. Investments in private equity funds are generally subject to a "lock-up" period during which investors may not request a redemption. Distributions prior to the expected termination date of the fund may be limited to dividends or proceeds arising from the liquidation of the fund's underlying investments. In addition, certain private equity funds provide an option to extend the lock-up period at either the sole discretion of the fund manager or upon agreement between the fund and the investors. As of March 31, 2021, investments in private equity funds were subject to lock-up periods as follows: 1 - 3 years 3 – 5 years 5 – 10 years Total Private equity funds – expected lock-up period remaining $ 48.3 $ 29.4 $ 41.9 $ 119.6 Investment in related party investment funds The following table provides the cost and fair value of the Company's investments in related party investment funds as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Cost Fair value Cost Fair value Third Point Enhanced LP $ 883.9 $ 1,200.8 $ 891.9 $ 1,055.6 Third Point Venture Offshore Fund I LP 8.0 8.0 — — Investment in related party investment funds, at fair value $ 891.9 $ 1,208.8 $ 891.9 $ 1,055.6 Investment in Third Point Enhanced LP On August 6, 2020, SiriusPoint, Third Point Reinsurance Company Ltd. (“Third Point Re BDA”) and Third Point Reinsurance (USA) Ltd. (“Third Point Re USA”) entered into the Third Amended and Restated Exempted Limited Partnership Agreement (“2020 LPA”) of Third Point Enhanced LP (“ TP Enhanced Fund ”) which became effective on February 26, 2021, except for the amendment to the calculation of the loss recovery account which became effective on December 31, 2020. In accordance with the 2020 LPA, Third Point Advisors LLC (“TP GP”) serves as the general partner of TP Enhanced Fund . The TP Enhanced Fund investment strategy, as implemented by Third Point LLC, is intended to achieve superior risk-adjusted returns by deploying capital in both long and short investments with favorable risk/reward characteristics across select asset classes, sectors and geographies. Third Point LLC identifies investment opportunities via a bottom-up, value-oriented approach to single security analysis supplemented by a top-down view of portfolio and risk management. Third Point LLC seeks dislocations in certain areas of the capital markets or in the pricing of particular securities and supplements single security analysis with an approach to portfolio construction that includes sizing each investment based on upside/downside calculations, all with a view towards appropriately positioning and managing overall exposures. Under the 2020 LPA, the Company has the right to withdraw funds monthly from TP Enhanced Fund to meet capital adequacy requirements and to satisfy financing obligations. The Company may also withdraw its investment upon the occurrence of certain events specified in the 2020 LPA, including, to meet capital adequacy requirements, to prevent a negative credit rating, for risk management purposes or to satisfy financing obligations, subject to certain limitations on such withdrawals as specified in the 2020 LPA, and may withdraw its investment in full on the first quarter end date after the 5-year anniversary of the closing date of the acquisition of Sirius Group (i.e. March 31, 2026) and each successive two-year anniversary of such date. The Company is also entitled to withdraw funds from the TP Enhanced Fund in order to satisfy its risk management guidelines, upon prior written notice to the TP GP, in an amount not to exceed 20% of the sum of (x) the aggregate opening balances of our capital account and (y) the aggregate amount of capital contributions credited to our capital account. As of March 31, 2021, the Company had no unfunded commitments related to TP Enhanced Fund. Investment in Third Point Venture Offshore Fund I LP On March 1, 2021, Third Point Re BDA entered into the Amended and Restated Exempted Limited Partnership Agreement (“2021 Venture LPA”) of Third Point Venture Offshore Fund I LP (“TP Venture Fund”) which became effective on March 1, 2021. In accordance with the 2021 Venture LPA, Third Point Venture GP LLC (“TP Venture GP”) serves as the general partner of TP Venture Fund. The TP Venture Fund investment strategy, as implemented by Third Point LLC, is to generate attractive risk-adjusted returns through a concentrated portfolio of investments in privately-held companies, primarily in the expansion through late/pre-IPO stage. The TP Venture Fund may also invest in early stage companies. Due the nature of the fund, withdrawals are not permitted. Distributions prior to the expected termination date of the fund include, but are not limited to, dividends or proceeds arising from the liquidation of the fund's underlying investments. As of March 31, 2021, the Company had $32.0 million of unfunded commitments related to TP Venture Fund. 19. Investments in unconsolidated entities The Company’s investments in unconsolidated entities are included within other long-term investments and consist of investments in common equity securities or similar instruments, which give the Company the ability to exert significant influence over the investee's operating and financial policies ("equity method eligible unconsolidated entities"). Such investments may be accounted for under either the equity method or, alternatively, the Company may elect to account for them under the fair value option. The following table presents the components of other long-term investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Equity method eligible unconsolidated entities, at fair value $ 218.0 $ — Other unconsolidated investments, at fair value (1) 255.1 4.0 Total other long-term investments (2) $ 473.1 $ 4.0 (1) Includes other long-term investments that are not equity method eligible. (2) There w ere no investm ents accounted for using the equity method as of March 31, 2021 and December 31, 2020. The Company has elected the fair value option to account for its equity method eligible investments accounted for as part of other long-term investments for consistency of presentation with the rest of its investment portfolio. The following table presents the Company’s ownership interests in investments in equity method eligible unconsolidated entities as of March 31, 2021: Investee March 31, Instrument Held BE Reinsurance Limited 24.9 % Common shares BioVentures Investors (Offshore) IV LP 73.0 % Units Camden Partners Strategic Fund V (Cayman), LP 39.4 % Units Diamond LS I LP 15.4 % Units Gateway Fund LP 22.9 % Units Monarch 12.8 % Units New Energy Capital Infrastructure Credit Fund LP 29.8 % Units New Energy Capital Infrastructure Offshore Credit Fund LP 29.8 % Units Pie Preferred Stock (1) 9.6 % Preferred shares Pie Series B Preferred Stock (1) 6.9 % Preferred shares Pie Series C Preferred Stock (1) 0.5 % Preferred shares Quintana Energy Partners 21.8 % Units Tuckerman Capital V LP 48.3 % Units Tuckerman Capital V Co-Investment I LP 49.0 % Units (1) The Company holds investments in several financing instruments of Pie Insurance Holdings, Inc.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. Fair value measurements U.S. GAAP disclosure requirements establish a framework for measuring fair value, including a three-level hierarchy for fair value measurements based upon the transparency of inputs to the valuation of an asset or liability. The three-level hierarchy of inputs is summarized below: • Level 1 – Quoted prices available in active markets/exchanges for identical investments as of the reporting date. • Level 2 – Observable inputs to the valuation methodology other than unadjusted quoted market prices for identical assets or liabilities in active markets. Level 2 inputs include, but are not limited to, prices quoted for similar assets or liabilities in active markets/exchanges, prices quoted for identical or similar assets or liabilities in markets that are not active and fair values determined through the use of models or other valuation methodologies. • Level 3 – Inputs are based all or in part on significant unobservable inputs for the investment, and include situations where there is little, if any, market activity for the investment. The inputs applied in the determination of fair value require significant management judgment and estimation. Inputs refer broadly to the assumptions that market participants would use in pricing the asset or liability, including assumptions about risk. For example, the risk inherent in a particular valuation technique used to measure fair value including such a pricing model and/or the risk inherent in the inputs to the valuation technique. Inputs may be observable or unobservable. Observable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability based on market data obtained from sources other than those of the reporting entity. Unobservable inputs are inputs that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and considers factors specific to the investment. The following tables present the Company’s investments, categorized by the level of the fair value hierarchy as of March 31, 2021 and December 31, 2020: March 31, 2021 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 594.6 $ — $ 594.6 Residential mortgage-backed securities — 392.2 — 392.2 Commercial mortgage-backed securities — 123.0 — 123.0 Corporate debt securities — 564.6 — 564.6 U.S. government and government agency 1,076.3 64.6 — 1,140.9 Non-U.S. government and government agency 24.9 96.4 — 121.3 U.S. states, municipalities and political subdivision — 0.9 — 0.9 Preferred stocks — — 2.8 2.8 Total debt securities 1,101.2 1,836.3 2.8 2,940.3 Fixed income mutual funds 1.8 — — 1.8 Common stocks 4.1 — — 4.1 Total equity securities 5.9 — — 5.9 Other long-term investments — — 311.2 311.2 Derivative assets 1.6 — 3.2 4.8 Loan participation — — 32.8 32.8 $ 1,108.7 $ 1,836.3 $ 350.0 3,295.0 Investments in funds valued at NAV 1,370.7 Total assets $ 4,665.7 Liabilities U.S. Government and government agency $ — $ 9.2 $ — $ 9.2 Total securities sold, not yet purchased — 9.2 — 9.2 Liability-classified capital instruments — — 135.0 135.0 Contingent consideration — — 1.5 1.5 Derivative liabilities — — 3.5 3.5 Total liabilities $ — $ 9.2 $ 140.0 $ 149.2 December 31, 2020 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 1.3 $ — $ 1.3 Residential mortgage-backed securities — 8.7 — 8.7 Bank debt — 0.4 — 0.4 Corporate debt securities — 37.7 — 37.7 U.S. Government and government agency — 53.2 — 53.2 Total debt securities — 101.3 — 101.3 Other long-term investments — — 4.0 4.0 Derivative assets — — 1.2 1.2 $ — $ 101.3 $ 5.2 106.5 Investments in funds valued at NAV 1,055.6 Total assets $ 1,162.1 Liabilities U.S. Government and government agency $ — $ 12.0 $ — $ 12.0 Total securities sold, not yet purchased — 12.0 — 12.0 Derivative liabilities — — 1.0 1.0 Total liabilities $ — $ 12.0 $ 1.0 $ 13.0 During the three months ended March 31, 2021, the Company made $nil (December 31, 2020 - $nil) of reclassifications of assets or liabilities between Levels 2 and 3. Valuation techniques The Company uses outside pricing services to assist in determining fair values for its investments. For investments in active markets, the Company uses the quoted market prices provided by outside pricing services to determine fair value. The outside pricing services the Company uses have indicated that they will only provide prices where observable inputs are available. In circumstances where quoted market prices are unavailable or are not considered reasonable, the Company estimates the fair value using industry standard pricing models and observable inputs such as benchmark yields, reported trades, broker-dealer quotes, issuer spreads, benchmark securities, bids, offers, prepayment speeds, reference data including research publications, and other relevant inputs. Given that many debt securities do not trade on a daily basis, the outside pricing services evaluate a wide range of fixed maturity investments by regularly drawing parallels from recent trades and quotes of comparable securities with similar features. The characteristics used to identify comparable debt securities vary by asset type and take into account market convention. The techniques and inputs specific to asset classes within the Company’s fixed maturity investments for Level 2 securities that use observable inputs are as follows: Asset-backed and mortgage-backed securities The fair value of mortgage and asset-backed securities is primarily priced by pricing services using a pricing model that uses information from market sources and leveraging similar securities. Key inputs include benchmark yields, reported trades, underlying tranche cash flow data, collateral performance, plus new issue data, as well as broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including issuer, vintage, loan type, collateral attributes, prepayment speeds, default rates, recovery rates, cash flow stress testing, credit quality ratings and market research publications. Corporate debt securities Corporate debt securities consist primarily of investment-grade debt of a wide variety of U.S. and non-U.S. corporate issuers and industries. The corporate fixed maturity investments are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources regarding the issuer of the security and obtain credit data, as well as other observations, from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The pricing services also consider the specific terms and conditions of the securities, including any specific features which may influence risk. U.S. government and government agency U.S. government and government agency securities consist primarily of debt securities issued by the U.S. Treasury and mortgage pass-through agencies such as the Federal National Mortgage Association, the Federal Home Loan Mortgage Corporation and the Government National Mortgage Association. Fixed maturity investments included in U.S. government and government agency securities are primarily priced by pricing services. When evaluating these securities, the pricing services gather information from market sources and integrate other observations from markets and sector news. Evaluations are updated by obtaining broker dealer quotes and other market information including actual trade volumes, when available. The fair value of each security is individually computed using analytical models which incorporate option adjusted spreads and other daily interest rate data. Non-U.S. government and government agency Non-U.S. government and government agency securities consist of debt securities issued by non-U.S. governments and their agencies along with supranational organizations (also known as sovereign debt securities). Securities held in these sectors are primarily priced by pricing services who employ proprietary discounted cash flow models to value the securities. Key quantitative inputs for these models are daily observed benchmark curves for treasury, swap and high issuance credits. The pricing services then apply a credit spread for each security which is developed by in-depth and real time market analysis. For securities in which trade volume is low, the pricing services utilize data from more frequently traded securities with similar attributes. These models may also be supplemented by daily market and credit research for international markets. U.S. states, municipalities, and political subdivisions The U.S. states, municipalities and political subdivisions portfolio contains debt securities issued by U.S. domiciled state and municipal entities. These securities are generally priced by independent pricing services using the techniques for U.S. government and government agency securities. Preferred stocks The fair value of preferred stocks is generally priced by independent pricing services using an evaluated pricing model that calculates the appropriate spread over a comparable security for each issue. Key inputs include exchange prices (underlying and common stock of same issuer), benchmark yields, reported trades, broker-dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, and reference data including sector, coupon, credit quality ratings, duration, credit enhancements, early redemption features and market research publications. Investments measured using Net Asset Value The Company values its investments in limited partnerships, including its investments in related party investment funds, at fair value. The Company has elected the practical expedient for fair value for these investments which is estimated based on the Company’s share of the net asset value (“NAV”) of the limited partnerships, as provided by the independent fund administrator, as the Company believes it represents the most meaningful measurement basis for the investment assets and liabilities. The NAV represents the Company’s proportionate interest in the members’ equity of the limited partnerships. The fair value of the Company's investments in certain hedge funds and certain private equity funds are also determined using NAV. The hedge fund's administrator provides quarterly updates of fair value in the form of the Company's proportional interest in the underlying fund's NAV, which is deemed to approximate fair value, generally with a three month delay in valuation. The private equity funds provide quarterly or semi-annual partnership capital statements with a three or six month delay which are used as a basis for valuation. These private equity investments vary in investment strategies and are not actively traded in any open markets. Due to a lag in reporting, some of the fund managers, fund administrators, or both, are unable to provide final fund valuations as of the Company's reporting date. In these circumstances, the Company estimates the return of the current period and uses all credible information available. This includes utilizing preliminary estimates reported by its fund managers and using other information that is available to the Company with respect to the underlying investments, as necessary. In order to assess the reasonableness of the NAVs, the Company performs a number of monitoring procedures on a monthly, quarterly and annual basis, to assess the quality of the information provided by the investment manager and fund administrator underlying the preparation of the NAV. These procedures include, but are not limited to, regular review and discussion of the fund’s performance with the investment manager. These investments are included in investment in funds valued at NAV and excluded from the presentation of investments categorized by the level of the fair value hierarchy. Level 3 Investments Level 3 valuations are generated from techniques that use assumptions not observable in the market. These unobservable assumptions reflect the Company's assumptions, that market participants would use in valuing the investment. Generally, certain securities may start out as Level 3 when they are originally issued but as observable inputs become available in the market, they may be reclassified to Level 2. The Company employs a number of procedures to assess the reasonableness of the fair value measurements for its other long-term investments, including obtaining and reviewing the audited annual financial statements of hedge funds and private equity funds and periodically discussing each fund's pricing with the fund manager. However, since the fund managers do not provide sufficient information to evaluate the pricing inputs and methods for each underlying investment, the inputs are considered to be unobservable. The fair values of the Company's investments in private equity securities, private debt instruments, certain private equity funds, and certain hedge funds have been classified as Level 3 measurements. They are carried at fair value and in the case of private equity securities and private debt instruments are initially valued based on transaction price and their valuation is subsequently estimated based on available evidence such as a market transaction in similar instruments and other financial information for the issuer. See Note 8 for additional information on the fair values of derivative financial instruments used for both risk management and investment purposes. Underwriting-related derivatives The Company has derivatives embedded in non-derivative host contracts that are required to be separated from the host contracts and accounted for at fair value with changes in fair value of the embedded derivative reported in other expenses. The Company’s embedded derivatives relate to interest crediting features in certain reinsurance and deposit contracts that vary based on the Company’s investment returns. The Company determines the fair value of the embedded derivatives using models developed by the Company. Other underwriting-related derivatives include reinsurance contracts that are accounted for as derivatives. These derivative contracts are initially valued at cost which approximates fair value. In subsequent measurement periods, the fair values of these derivatives are determined using internally developed discounted cash flow models. As the significant inputs used to price these derivatives are unobservable, the fair values of these contracts are classified as Level 3. The following table presents the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2021 and 2020: January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired (1) Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Preferred stocks $ — $ — $ — $ 2.8 $ — $ — $ 2.8 Other long-term investments 4.0 — 13.6 259.0 (1.0) 35.6 311.2 Derivative assets 1.2 — — 0.3 — 1.7 3.2 Loan participation — — — 32.8 — — 32.8 Total assets $ 5.2 $ — $ 13.6 $ 294.9 $ (1.0) $ 37.3 $ 350.0 Liabilities Liability-classified capital instruments $ — $ — $ (135.0) $ — $ — $ — $ (135.0) Contingent consideration — — — (0.7) — (0.8) (1.5) Derivative liabilities (1.0) — — (2.0) — (0.5) (3.5) Total liabilities $ (1.0) $ — $ (135.0) $ (2.7) $ — $ (1.3) $ (140.0) January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Asset-backed securities $ — $ — $ 4.4 $ — $ — $ — $ 4.4 Other long-term investments 4.0 — — — — — 4.0 Total assets $ 4.0 $ — $ 4.4 $ — $ — $ — $ 8.4 Liabilities Derivative liabilities $ — $ — $ — $ — $ — $ — $ — Total liabilities $ — $ — $ — $ — $ — $ — $ — (1) Includes amounts acquired as a result of the Sirius Group acquisition. (2) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in net investment income (loss) in the condensed consolidated statements of income (loss). Realized and unrealized gains (losses) related to underwriting-related derivative assets and liabilities are included in other underwriting expenses, net of foreign exchange (gains) losses, in the condensed consolidated statements of income (loss). For assets and liabilities that were transferred into Level 3 during the period, gains (losses) are presented as if the assets or liabilities had been transferred into Level 3 at the beginning of the period; similarly, for assets and liabilities that were transferred out of Level 3 during the period, gains (losses) are presented as if the assets or liabilities had been transferred out of Level 3 at the beginning of the period. Significant unobservable inputs The table below presents information about the significant unobservable inputs used for recurring fair value measurements for certain Level 3 instruments as of March 31, 2021, and includes only those instruments for which information about the inputs is reasonably available to the Company, such as data from independent third-party valuation service providers and from internal valuation models. March 31, 2021 Assets (Liability) Fair Value Valuation Technique Unobservable input Private equity securities (4) $ 152.0 Subject company transaction approach Share price range 19.84 - 23.34 Private equity funds (3) 80.2 Net asset value discount Discount range 50% - 95% Private equity securities (1) 39.6 Share price of recent transaction Purchase share price 50.79 Loan participations (5) 32.8 Share price of recent transaction Comparable yields Range - 4.91%-7.82% Median - 5.92% Private equity securities (1) 15.0 Multiple of GAAP book value Book value multiple Range - 0.73x-0.91x Median - 0.82x Common Stock (1) 10.0 Purchase price of recent transaction Purchase price 10.0 Private debt instrument (1) 6.5 Discounted cash flow Discount yield Range - 6.55%-7.03% Median - 6.73% Preferred stock (1) 3.0 Purchase price of recent transaction Purchase price 3.0 Preferred stocks (5) 2.8 Share price of recent transaction Share price 2.8 Promissory note (1) 2.5 Purchase price of recent transaction Purchase price 2.5 Preferred stock (1) 1.1 Purchase price of recent transaction Purchase price 1.1 Membership Interest (1) 1.0 Purchase price of recent transaction Purchase price 1.0 Equity warrants (2) 0.3 Option pricing model Strike price 0.2 Private equity securities (1) 0.3 Purchase price of recent transaction Purchase price 0.3 Weather derivatives (2) (0.3) Third party appraisal Broker quotes (0.3) Contingent consideration (1) (1.5) External valuation model Discounted future payments (1.5) Currency swaps (2) (2.2) Third party appraisal Broker quotes (2.2) Upside rights (1) (6.5) External valuation model Share price (6.5) Private warrants (1) (7.3) Black Scholes pricing model Share price 1.81 Contingent value rights (1) (27.0) External valuation model Share price 5.91 Series A preference shares (1) (40.8) External valuation model Share price (40.8) Merger warrants (1) $ (53.4) External valuation model Share price 2.54 (1) Each asset type consists of one security except as indicated below. (2) See Note 8 for discussion of derivative instruments. (3) Represents multiple private equity funds where a discount on net asset value was taken. (4) Represents various tranches of the Company's investment in Pie. (5) Represents multiple securities held under the same Investment Management Agreement. Financial instruments disclosed, but not carried at fair value The Company uses various financial instruments in the normal course of its business. The carrying values of cash, accrued investment income, certain other assets, certain other liabilities, and other financial instruments not included in the table below approximated their fair values at March 31, 2021 and December 31, 2020, due to their respective short maturities. The following table includes financial instruments for which the carrying value differs from the estimated fair values at March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Fair Value Carrying Value Fair Value Carrying Value 2017 SEK Subordinated Notes (1) $ 307.2 $ 307.9 n/a n/a 2016 SIG Senior Notes (1) 405.0 406.8 n/a n/a 2015 TPRUSA Senior Notes (2) $ 117.5 $ 114.3 $ 117.8 $ 114.3 (1) These financial instruments are not actively traded. Fair value is estimated by internal pricing and therefore considered a Level 3 measurement. (2) Fair value based on observable inputs and considered a Level 2 measurement.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	8. Derivatives As a result of the acquisition of Sirius Group, the Company now holds derivative financial instruments for both risk management and investment purposes. Interest rate cap The Company entered into an interest rate swap ("Interest Rate Cap ") with two fina ncial institutions where it paid an upfront premium and in return receives a series of quarterly payments based on the 3-month London Interbank Offered Rate at the time of payment. The Interest Rate Cap does not qualify for hedge accounting. Changes in fair value are recognized as unrealized gains or losses and are presented within other revenues. The fair value of the Interest Rate Cap has been estimated using a single broker quote and, accordingly, has been classified as a Level 3 measurement as of March 31, 2021. Collateral held is recorded with an equal amount recognized as a liability to return collateral. The Company’s liability to return that collateral is based on the amounts provided by the counterparties and investment earnings thereon. As of March 31, 2021, the Company held collateral balance s of $0.1 million. Foreign currency risk derivatives The Company executes foreign currency forwards, call options, swaps, and futures to manage foreign currency exposure. The foreign currency risk derivatives are not designated or accounted for under hedge accounting. Changes in fair value are recognized as unrealized gains or losses and are presented within foreign exchange gains. The fair value of the swaps and forwards are estimated using a single broker quote, and accordingly, are classified as a Level 3 measurement. The fair value of the futures is widely available and have quoted prices in active markets, and accordingly, were classified as a Level 1 measurement. The Company did not provide or hold any collateral associated with the foreign currency risk derivatives. Equity warrants The Company holds restricted equity warrants as part of its investment strategy. The equity warrants are not designated or accounted for under hedge accounting. Changes in fair value are presented within net realized and unrealized investment gains. The fair value of the equity warrants is estimated using a single broker quote and accordingly, classified as a Level 3 measurement. The Company did not provide or hold any coll ateral associated with the equity warrants. The following table summarizes information on the classification and amount of the fair value of derivatives not designated as hedging instruments within the Company's condensed consolidated balance sheets as at March 31, 2021: March 31, 2021 Derivatives not designated as hedging instruments Notional Value Derivative assets at fair value (1) Derivative liabilities at fair value (2) Interest rate cap (3) $ 250.0 $ — $ — Foreign currency swaps 40.0 — 2.3 Weather derivatives 31.2 — 0.2 Foreign currency futures contracts (3) 100.8 — — Foreign currency call options 50.6 1.6 — Equity warrants $ 0.3 $ 0.3 $ — (1) Derivative assets are classified within other assets in the Company's condensed consolidated balance sheets at March 31, 2021. (2) Derivative liabilities are classified within accounts payable, accrued expenses and other liabilities in the Company's condensed consolidated balance sheets at March 31, 2021. (3) De minimis as of March 31, 2021. (4) The Company did not hold the above derivative instruments as of December 31, 2020. The following table summarizes information on the classification and net impact on earnings, recognized in the Company's condensed consolidated statements of income (loss) relating to derivatives during the three months ended March 31, 2021: Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings 2021 Foreign currency swaps Foreign exchange gains $ (0.4) Weather derivatives Net corporate and other expenses (0.1) Foreign currency futures contracts Foreign exchange gains (3.7) Foreign currency call options Foreign exchange gains $ (1.6) Underwriting-related derivatives The following tables identify the listing currency, fair value and notional amounts of underwriting-related derivatives included in the condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Derivative assets Listing currency (1) Fair Value Notional Amounts (2) Fair Value Notional Amounts (2) Reinsurance contracts accounted for as derivative assets GBP $ 2.9 $ 2.9 $ 1.2 $ 4.2 $ 2.9 $ 2.9 $ 1.2 $ 4.2 March 31, 2021 December 31, 2020 Derivative liabilities Listing currency (1) Fair Value Notional Amounts (2) Fair Value Notional Amounts (2) Reinsurance contracts accounted for as derivative liabilities GBP $ 1.0 $ 13.4 $ 1.0 $ 15.7 $ 1.0 $ 13.4 $ 1.0 $ 15.7 (1) GBP = British Pound. (2) The absolute notional exposure represents the Company’s derivative activity as of March 31, 2021 and December 31, 2020, which is representative of the volume of derivatives held during the period.

Loss and loss adjustment expens

Loss and loss adjustment expense reserves	3 Months Ended
	Mar. 31, 2021
Insurance [Abstract]
Loss and loss adjustment expense reserves	9. Loss and loss adjustment expense reserves The following table represents the activity in the loss and loss adjustment expense reserves for the three months ended March 31, 2021 and 2020: 2021 2020 Gross reserves for loss and loss adjustment expenses, beginning of period $ 1,310.1 $ 1,111.7 Less: loss and loss adjustment expenses recoverable, beginning of period (14.4) (5.5) Less: deferred charges on retroactive reinsurance contracts (6.0) (6.7) Net reserves for loss and loss adjustment expenses, beginning of period 1,289.7 1,099.5 Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in: Current year 147.7 92.2 Prior years 0.4 (4.4) Total incurred loss and loss adjustment expenses 148.1 87.8 Net loss and loss adjustment expenses paid in respect of losses occurring in: Current year (15.9) (10.1) Prior years (117.2) (74.0) Total net paid losses (133.1) (84.1) Foreign currency translation (10.6) (10.2) Amounts acquired as a result of Sirius Group acquisition (1) 2,467.8 — Net reserves for loss and loss adjustment expenses, end of period 3,761.9 1,093.0 Plus: loss and loss adjustment expenses recoverable, end of period 492.6 6.9 Plus: deferred charges on retroactive reinsurance contracts (2) 4.8 8.0 Gross reserves for loss and loss adjustment expenses, end of period $ 4,259.3 $ 1,107.9 (1) Represents the fair value of Sirius Group’s reserves for claims and claim expenses, net of reinsurance recoverables, acquired at February 26, 2021. See Note 3 for additional information related to the acquisition of Sirius Group. (2) Deferred charges on retroactive contracts are recorded in other assets on the Company’s condensed consolidated balance sheets. For the three months ended March 31, 2021, the Company recorded $0.4 million of net unfavorable prior year loss reserve development. Prior to the acquisition of Sirius Group, many of the Company’s contracts had sliding scale or profit commissions whereby loss reserve development could be offset by changes in acquisition costs that vary inversely with loss experience. The $4.4 million net decrease in prior years’ reserves for the three months ended March 31, 2020 included $11.0 million of net favorable reserve development related to decreases in loss reserve estimates, partially offset by a $6.6 million increase in loss reserves resulting from increases in premium earnings estimates on certain contracts. The net decrease in loss reserves as well as the impact of any offsetting changes in acquisition costs resulted in a $3.2 million improvement in the net underwriting results for the three months ended March 31, 2020.

Third party reinsurance

Third party reinsurance	3 Months Ended
	Mar. 31, 2021
Insurance [Abstract]
Third party reinsurance	10. Third party reinsurance In the normal course of business, the Company seeks to protect its businesses from losses due to concentration of risk and losses arising from catastrophic events by reinsuring with third-party reinsurers. Additionally, retrocession can be used as a mechanism to share the risks and rewards of business written and therefore can be used as a tool to align the Company’s interests with those of its counterparties. The Company remains liable for risks reinsured in the event that the reinsurer does not honor its obligations under reinsurance contracts. Premiums ceded for the three months ended March 31, 2021 and 2020 were $56.3 million and $2.5 million, respectively. Loss and loss adjustment expenses recoverable from the retrocessionaire are recorded as assets. As of March 31, 2021, the Company had loss and loss adjustment expenses recoverable of $492.6 million (December 31, 2020 - $14.4 million). Because retrocessional reinsurance contracts do not relieve the Company of its obligation to its insureds, the collectability of balances due from the Company's reinsurers is important to its financial strength. The Company monitors the financial strength and ratings of retrocessionaires on an ongoing basis. See Note 11 for additional information.

Allowance for expected credit l

Allowance for expected credit losses	3 Months Ended
	Mar. 31, 2021
Receivables [Abstract]
Allowance for expected credit losses	11. Allowance for expected credit losses The Company is exposed to credit losses primarily through sales of its insurance and reinsurance products and services. The financial assets in scope of the current expected credit losses impairment model primarily include the Company’s insurance and reinsurance balances receivable and loss and loss adjustment expenses recoverable. The Company pools these amounts by counterparty credit rating and applies a credit default rate that is determined based on the studies published by the rating agencies (e.g., AM Best, S&P). In circumstances where ratings are unavailable, the Company applies an internally developed default rate based on historical experience, reference data including research publications, and other relevant inputs. The Company's assets in scope of the current expected credit loss assessment as of March 31, 2021 and December 31, 2020 are as follows: March 31, December 31, 2020 Insurance and reinsurance balances receivable, net $ 1,613.8 $ 441.9 Loss and loss adjustment expenses recoverable, net 492.6 14.4 Other assets (1) 15.9 — Total assets in scope $ 2,122.3 $ 456.3 (1) Relates to MGU trade receivables included in other assets in the Company’s condensed consolidated balance sheets. The Company’s allowance for expected credit losses was $18.0 million and $0.6 million as of March 31, 2021 and December 31, 2020, respectively. For the three months ended March 31, 2021 and 2020, the Company recorded current expected credit losses of $17.4 million and $0.2 million, respectively. The Company recognized the allowance for credit losses in accordance with ASC 326 upon initial recognition of the Sirius Group assets within the scope of the standard. An allowance of $16.8 million was re-established in the first quarter ended March 31, 2021 as related to Sirius Group assets. These amounts are included in net corporate and other expenses in the condensed consolidated statements of income (loss).

Deposit accounted contracts

Deposit accounted contracts	3 Months Ended
	Mar. 31, 2021
Insurance [Abstract]
Deposit accounted contracts	12. Deposit accounted contracts The following table represents activity for the deposit contracts for the three months ended March 31, 2021 and year ended December 31, 2020: March 31, December 31, 2020 Balance, beginning of period $ 153.0 $ 172.3 Consideration received 0.4 0.5 Net investment expense allocation 0.8 0.9 Payments (3.4) (20.8) Foreign currency translation (0.1) 0.1 Balance, end of period $ 150.7 $ 153.0

Debt and letter of credit facil

Debt and letter of credit facilities	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Debt and letter of credit facilities	13. Debt and letter of credit facilities Debt obligations The following table represents a summar y of the Company’s debt obl igations on its condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Amount Effective rate (1) Amount Effective rate (1) 2017 SEK Subordinated Notes, at face value (2) $ 315.1 4.1 % n/a n/a Unamortized discount (7.2) n/a 2017 SEK Subordinated Notes, carrying value 307.9 n/a 2016 SIG Senior Notes, at face value 400.0 4.5 % n/a n/a Unamortized premium 6.8 n/a 2016 SIG Senior Notes, carrying value (2) 406.8 n/a 2015 TPRUSA Senior Notes, at face value 115.0 7.0 % 115.0 7.0 % Unamortized issuance costs (0.7) (0.7) 2015 TPRUSA Senior Notes, carrying value 114.3 114.3 Total debt $ 829.0 $ 114.3 (1) Effective rate considers the effect of the debt issuance costs, discount, and premium. (2) In connection with the acquisition of Sirius Group, SiriusPoint assumed the outstanding debt of Sirius Group. 2017 SEK Subordinated Notes On September 22, 2017, Sirius Group issued floating rate callable subordinated notes denominated in Swedish kronor ("SEK") in the amount of SEK 2,750.0 million (or $346.1 million on date of issuance) at a 100% issue price ("2017 SEK Subordinated Notes"). The 2017 SEK Subordinated Notes were issued in an offering that was exempt from the registration requirements of the Securities Act of 1933 (the "Securities Act"). The 2017 SEK Subordinated Notes bear interest on their principal amount at a floating rate equal to the applicable Stockholm Interbank Offered Rate for the relevant interest period plus an applicable margin, payable quarterly in arrears on March 22, June 22, September 22 and December 22 of each year until maturity in September 2047. Beginning on September 22, 2022, the 2017 SEK Subordinated Notes may be redeemed, in whole or in part, at the Company’s option. The Company was in compliance with all debt covenants as of and for the period ended March 31, 2021. The Company recorde d $1.2 million of interest expense, inclusive of amortization of discount, on the 2017 SEK Subordinated Notes for the three months ended March 31, 2021. The Company also recognized $13.4 million of foreign exchange gains of the 2017 SEK Subordinated Notes into USD from SEK for the three months ended March 31, 2021. 2016 SIG Senior Notes On N ovember 1, 2 016, Sirius Group is sued $400.0 million face value of senior unsecured notes ("2016 SIG Senior Notes") at an issue price of 99.2% for net proceeds of $392.4 million after taking into effect both deferrable and non-deferrable issuance costs. The 2016 SIG Senior Notes were issued in an offering that was exempt from the registration requirements of the Securities Act. The 2016 SIG Senior Notes bear an annual interest rate of 4.6%, payable semi-annually in arrears on May 1 and November 1 of each year until maturity in November 2026. The Company was in compliance with all debt covenants as of and for the period ended March 31, 2021. The Company recorded $1.7 million of interest expense, inclusive of amortization of premium, on the 2016 SIG Senior Notes, for the three months ended March 31, 2021. 2015 TPRUSA Senior Notes As of March 31, 2021, Third Point Re (USA) Holdings, Inc. (“TPRUSA”) had outstanding debt obligations consisting of an aggregate principal amount of $115.0 million of senior unsecured notes (the “2015 TPRUSA Senior Notes”) due February 13, 2025. The 2015 TPRUSA Senior Notes bear interest at 7.0% and interest is payable semi-annually on February 13 and August 13 of each year. The 2015 TPRUSA Senior Notes are fully and unconditionally guaranteed by SiriusPoint and, in certain circumstances specified in the indenture governing the 2015 TPRUSA Senior Notes , certain existing or future subsidiaries of the Company may be required to guarantee the 2015 TPRUSA Senior Notes. The Company was in compliance with all debt covenants as of and for the periods ended March 31, 2021 and December 31, 2020. The Company recorde d $2.0 million of interest expense, inclusive of amortization of issuance costs, on the 2015 TPRUSA Senior Notes for the three months ended March 31, 2021 (2020 - $2.0 million). Interest expense Total interest expense incurred by the Company for its indebtedness for the three months ended March 31, 2021 was $4.9 million (2020 - $2.0 million). Standby letter of credit facilities As of March 31, 2021, the Company had entered into the following letter of credit facilities: Letters of Credit Collateral Committed Capacity Issued Cash and Cash Equivalents Debt securities Committed - Secured letters of credit facilities $ 2,026.0 $ 1,089.5 $ 168.2 $ 751.8 Uncommitted - Secured letters of credit facilities n/a 296.1 295.4 — $ 1,385.6 $ 463.6 $ 751.8 The Company’s secured letter of credit facilities are bilateral agreements that generally renew on an annual basis. The letters of credit issued under the secured letter of credit facilities are fully collateralized. The above referenced facilities are subject to various affirmative, negative and financial covenants that the Company considers to be customary for such borrowings, including certain minimum net worth and maximum debt to capitalization standards. See Note 5 for additional information. Revolving credit facility Effective February 26, 2021, the Company entered into a three-year, $300.0 million senior unsecured revolving credit facility (the “Facility”) with JPMorgan Chase Bank, N.A. as administrative agent. The Facility includes an option, subject to satisfaction of certain conditions including agreement of lenders representing greater than a majority of commitments, for the Company to request an extension by such lenders of the maturity date of the Facility by an additional 12 months. The Facility provides access to loans for working capital and general corporate purposes, and letters of credit to support obligations under insurance and reinsurance agreements, retrocessional agreements and for general corporate purposes. Loans and letters of credit under the Facility will become available, subject to customary conditions precedent. As of March 31, 2021, there were no outstanding borrowings under the Facility.

Net investment income (loss)

Net investment income (loss)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Net investment income (loss)	14. Net investment income (loss) Net investment income (loss) for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ (7.8) $ 19.7 Equity securities 0.3 — Other long-term investments 49.2 — Net investment income (loss) from investments in related party investment funds 153.2 (200.8) Net investment income (loss) before other investment expenses and investment loss on cash and cash equivalents 194.9 (181.1) Other investment expenses (1.0) (0.2) Net investment loss on cash and cash equivalents (7.4) (3.7) Net investment income (loss) $ 186.5 $ (185.0) Net realized and unrealized gains on investments Net realized and unrealized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Gross realized gains $ 19.3 $ 2.7 Gross realized losses (0.4) (1.7) Net realized gains on investments (1) 18.9 1.0 Net unrealized gains on investments (2) 12.6 10.6 Net realized and unrealized gains on investments (3) $ 31.5 $ 11.6 (1) Includes realized gains (losses) due to foreign currency of $2.1 million for the three months ended March 31, 2021 (2020 - $(0.1) million). (2) Includes unrealized losses due to foreign currency of $(16.3) million for the three months ended March 31, 2021 (2020 - $(8.6) million). (3) Excludes realized and unrealized gains (losses) on the Company’s investments in related party investment funds. Net realized investment gains Net realized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ 6.3 $ (0.7) Equity securities 0.4 — Other long-term investments 9.9 — Net investment income on cash and cash equivalents 2.3 1.7 Net realized investment gains $ 18.9 $ 1.0 Net unrealized investment gains Net unrealized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ (16.9) $ 19.4 Equity securities (0.1) — Other long-term investments 39.3 — Net investment loss on cash and cash equivalents (9.7) (8.8) Net unrealized investment gains $ 12.6 $ 10.6 The following table summarizes the amount of total gains included in earnings attributable to unrealized investment gains – Level 3 investments for the three months ended March 31, 2021 and 2020: 2021 2020 Other long-term investments $ 35.6 $ — Total unrealized investment gains – Level 3 investments $ 35.6 $ —

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income taxes	15. Income taxes The Company provides for income tax expense or benefit based upon pre-tax income or loss reported in the condensed consolidated statements of income (loss) and the provisions of currently enacted tax laws. The Company and its Bermuda subsidiaries are incorporated under the laws of Bermuda and are subject to Bermuda law with respect to taxation. Under current Bermuda law, the Company and its Bermuda subsidiaries are not subject to any income or capital gains taxes in Bermuda. In the event that such taxes are imposed, the Company and its Bermuda subsidiaries would be exempted from any such taxes until March 2035 under the Tax Assurance Certificates issued to such entities pursuant to the Bermuda Exempted Undertakings Tax Protection Act of 1966, as amended. Prior to the acquisition of Sirius Group on February 26, 2021, the Company had one operating subsidiary incorporated in Bermuda, Third Point Re USA, which made an election to pay tax in the United States of America under Section 953(d) of the U.S. Internal Revenue Code of 1986, as amended. Subsequent to the acquisition of Sirius Group, the Company has subsidiaries and branches that operate in various other jurisdictions around the world that are subject to tax in the jurisdictions in which they operate. The jurisdictions in which the Company's subsidiaries and branches are subject to tax are Australia, Belgium, Canada, Germany, Gibraltar, Hong Kong (China), Ireland, Luxembourg, Malaysia, Singapore, Spain, Sweden, Switzerland, the United Kingdom, and the United States. For the three months ended March 31, 2021, the Company recorded income tax expense of $9.8 million (2020 - $0.4 million) on pre-tax income (loss) of $142.2 million (2020 - $(183.2) million). The effective tax rate for the three months ended March 31, 2021 was 6.9%. The difference between the effective tax rate on income from continuing operations and the Swedish statutory tax rate of 20.6% (the rate at which the majority of the Company's worldwide operations are taxed after the acquisition of Sirius Group) is primarily because of income recognized in jurisdictions with lower tax rates than Sweden and adjustments required under applicable U.S. GAAP guidance, which are based on the annual estimated effective tax rate. In arriving at the annual effective tax rate for the three months ended March 31, 2021 and 2020, the Company took into consideration all year-to-date income and expense items including the change in unrealized investment gains (losses) and realized investment gains (losses) and such items on a forecasted basis for the remainder of each year. Based on applicable U.S. GAAP guidance, jurisdictions with a projected loss for the full year where no tax benefit can be recognized are excluded from the estimation of the annual effective tax rate. The Tax Cuts and Jobs Act ("TCJA") includes a Base Erosion and Anti-Abuse Minimum Tax ("BEAT") provision, which is essentially a minimum tax on certain otherwise deductible payments made by U.S. entities to non-U.S. affiliates, including cross-border interest payments and reinsurance premiums paid or ceded. The statutory BEAT rate is 10% through 2025, and then rises to 12.5% in 2026 and thereafter. The TCJA also includes provisions for Global Intangible Low-Taxed Income ("GILTI") under which taxes on foreign income are imposed on the excess of a deemed return on tangible assets of certain foreign subsidiaries. Consistent with accounting guidance, the Company will treat BEAT as an in period tax charge when incurred in future periods for which no deferred taxes need to be provided and has made an accounting policy election to treat GILTI taxes in a similar manner. No pro vision for income taxes related to BEAT or GILTI was recorded as of March 31, 2021 and December 31, 2020. The Company has capital and liquidity in many of its subsidiaries, some of which may reflect undistributed earnings. If such capital or liquidity were to be paid or distributed to the Company or to one of its intermediary subsidiaries as dividends or otherwise, they may be subject to withholding tax by the source country and/or income tax by the recipient country. The Company generally intends to operate, and manage its capital and liquidity, in a tax-efficient manner. However, the applicable tax laws in relevant countries are still evolving, including in connection with guidance and proposals from the Organisation for Economic Cooperation and Development (“OECD”). Accordingly, such payments or distributions may be subject to income or withholding tax in jurisdictions where they are not currently taxed or at higher rates of tax than currently taxed, and the applicable tax authorities could attempt to apply income or withholding tax to past earnings or payments. Deferred tax asset, net of valuation allowance As of March 31, 2021, the Company has recorded net deferred tax asset, net of valuation allowance, of $33.5 million. $71.4 million relates to net deferred tax assets in U.S. subsidiaries, $147.0 million relates to net deferred tax assets in Luxembourg subsidiaries, $6.1 million relates to net deferred tax liabilities in UK subsidiaries, $170.9 million relates to net deferred tax liabilities in Sweden subsidiaries, and $7.9 million relates to other net deferred tax liabilities. The Company records a valuation allowance against deferred tax assets if it becomes more likely than not that all or a portion of deferred tax assets will not be realized. Changes in valuation allowances from period to period are included in income tax expense in the period of change. In determining whether or not a valuation allowance, or change therein, is warranted, the Company considers factors such as prior earnings history, expected future earnings, carryback and carryforward periods and strategies that if executed would result in the realization of a deferred tax asset. It is possible that certain planning strategies or projected earnings in certain subsidiaries may not be feasible to utilize the entire deferred tax asset, which could result in material changes to the Company's deferred tax assets and tax expense. Uncertain tax positions Recognition of the benefit of a given tax position is based upon whether a company determines that it is more likely than not that a tax position will be sustained upon examination based upon the technical merits of the position. In evaluating the more likely than not recognition threshold, the Company must presume that the tax position will be subject to examination by a taxing authority with full knowledge of all relevant information. If the recognition threshold is met, then the tax position is measured at the largest amount of benefit that is more than 50% likely of being realized upon ultimate settlement. As of March 31, 2021, the total reserve for unrecognized tax benefits is $3.1 million. If the Company determines in the future that its reserves for unrecognized tax benefits on permanent differences and interest and penalties are not needed, the reversal of $2.5 million of such reserves as of March 31, 2021 would be recorded as an income tax benefit and would impact the effective tax rate. If the Company determines in the future that its reserves for unrecognized tax benefits on temporary differences are not needed, the reversal of $0.6 million of such reserves as of March 31, 2021 would not impact the effective tax rate due to deferred tax accounting but would accelerate the payment of cash to the taxing authority. With few exceptions, which are not material, the Company is no longer subject to U.S. federal, state or non-U.S. income tax examinations by tax authorities for years before 2016.

Shareholders' equity

Shareholders' equity	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Shareholders' equity	16. Shareholders' equity Common shares The following table presents a summary of the common shares issued and outstanding as of and for the three months ended March 31, 2021 and 2020: 2021 2020 Common shares issued, beginning of period 95,582,733 94,225,498 Issuance of common shares, net of forfeitures and shares withheld 2,081,001 283,008 Performance restricted shares granted, net of forfeitures and shares withheld (197,418) 372,723 Issuance of common shares for Sirius Group acquisition 58,331,196 — Issuance of common shares to related party 6,093,842 — Common shares issued, end of period 161,891,354 94,881,229 The Company’s authorized share capital consists of 300,000,000 common shares with a par value of $0.10 each. During the three months ended March 31, 2021 and 2020, the Company did not pay any dividends to its common shareholders. Preference shares The Company’s authorized share capital also consists of 30,000,000 preference shares with a par value of $0.10 each. Series B preference shares On February 26, 2021, the previous Sirius Group preference shareholders exchanged their existing Series B preference shares of Sirius Group in return for 8,000,000 new Series B preference shares, par value $0.10, of the Company. Dividends on the Series B preference shares will be cumulative and payable quarterly in arrears at an initial rate of 8.0% per annum. The preference shareholders will have no voting rights with respect to the Series B preference shares unless dividends have not been paid for six dividend periods, whether or not consecutive, in which case the holders of the Series B preference shares will have the right to elect two directors. The dividend rate will reset on each five-year anniversary of issuance at a rate equal to the 5-year U.S. treasury rate at such time plus 7.298%. The Series B preference shares are perpetual and have no fixed maturity date. The Series B preference shares will provide for redemption rights by the Company (i) in whole, or in part, on each five-year anniversary of issuance at 100%, (ii) in whole, but not in part, (a) upon certain rating agency events, at 102%, (b) upon certain capital disqualification events, at 100%, and (c) upon certain tax events, at 100%.

Share-based compensation

Share-based compensation	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-based compensation	17. Share-based compensation The following table provides the total share-based compensation expense included in general and administrative expenses during the three months ended March 31, 2021 and 2020: 2021 2020 Restricted shares with service condition $ 2.0 $ 0.5 Restricted shares with service and performance condition 0.3 1.1 $ 2.3 $ 1.6 As of March 31, 2021, the Company had $37.9 million (December 31, 2020 - $14.2 million) of unamortized share compensation expense, which is expected to be amortized over a weighted average period of 2.0 years (December 31, 2020 - 1.9 years). Options The options activity for the three months ended March 31, 2021 was as follows: Number of Weighted average Balance as of January 1, 2021 8,255,810 13.45 Granted 2,183,853 10.78 Balance as of March 31, 2021 10,439,663 12.89 The share options issued to management under the Share Incentive Plan are subject to a service condition. The fair value of share options issued were estimated on the grant date using the Black-Scholes option-pricing model. The following table summarizes information about the Company’s management and director share options outstanding and exercisable as of March 31, 2021: Options outstanding Options exercisable Range of exercise prices Number of Weighted average Remaining contractual life Number of Weighted average $9.83 - $10.89 6,528,039 $ 9.98 0.6 years 6,528,039 $ 9.98 $15.00 - $16.89 2,190,696 15.75 2.7 years 1,790,696 15.92 $20.00 - $25.05 1,720,928 20.28 1.0 years 1,720,928 20.28 10,439,663 $ 12.89 1.1 years 10,039,663 $ 11.06 Restricted share awards with service condition Restricted share award activity for the three months ended March 31, 2021 and year ended December 31, 2020 was as follows: Number of non- Weighted Balance as of January 1, 2020 340,767 $ 11.83 Granted 1,029,373 8.30 Forfeited (16,434) 9.77 Vested (182,648) 10.10 Balance as of January 1, 2021 1,171,058 8.80 Granted 1,188,380 10.21 Vested (204,864) 9.89 Balance as of March 31, 2021 2,154,574 $ 9.47 Restricted share awards with service condition vest either ratably or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment or service and transferability. Restricted share units with service condition As a result of the acquisition of Sirius Group, Sirius Group's outstanding restricted share units ("RSUs") were converted to Company RSUs. RSU activity for the three months ended March 31, 2021 was as follows: Number of non- Weighted Balance as of January 1, 2021 — $ — Granted 4,935,144 10.21 Vested (2,051,730) 10.21 Balance as of March 31, 2021 2,883,414 10.21 RSUs with service condition vest either ratably or at the end of the required service period and contain certain restrictions during the vesting period, relating to, among other things, forfeiture in the event of termination of employment or service and transferability. Restricted share awards with service and performance condition Restricted share award activity for the restricted shares with a service and performance condition for the three months ended March 31, 2021 and year ended December 31, 2020 were as follows: Number of non- Number of non- Weighted average grant date fair value of shares probable of vesting Balance as of January 1, 2020 1,890,529 1,314,036 $ 12.43 Granted 749,322 499,542 9.46 Forfeited (372,476) (39,214) 12.12 Vested (504,440) (504,440) 12.16 Change in estimated restricted shares considered probable of vesting n/a 132,656 11.28 Balance as of January 1, 2021 1,762,935 1,402,580 10.98 Forfeited (166,702) — 14.03 Vested (300,469) (300,469) 14.03 Change in estimated restricted shares considered probable of vesting n/a (238,279) 10.33 Balance as of March 31, 2021 1,295,764 863,832 $ 10.11

Variable interest entities

Variable interest entities	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable interest entities	18. Variable interest entities The Company consolidates the results of operations and financial position of every voting interest entity ("VOE") in which it has a controlling financial interest and variable interest entities (“VIE”) in which it is considered to be the primary beneficiary in accordance with guidance in ASC 810, Consolidation . The consolidation assessment, including the determination as to whether an entity qualifies as a VOE or VIE, depends on the facts and circumstances surrounding each entity. Consolidated variable interest entities Alstead Re As a result of the acquisition of Sirius Group, the Company has consolidated the results of Alstead Re Insurance Company (“Alstead Re”) in its condensed consolidated financial statements beginning February 26, 2021. Alstead Re is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company determined that Alstead Re is a VIE for which the Company is the primary beneficiary as it has power over the activities that most significantly impact the economic performance. As of March 31, 2021, Alstead Re’s assets and liabilities included in the Company’s condensed consolidated balance sheets were $7.3 million and $2.9 million, respectively. Arcadian In September 2020, the Company co-founded Arcadian Risk Capital Ltd. (“Arcadian”), a managing general agent incorporated in Bermuda writing business on behalf of the Company. Arcadian commenced operations on October 1, 2020. The Company’s ownership in Arcadian as of March 31, 2021 was 49%, representing 980,000 common shares at $1.00 par value. Arcadian is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company concluded that it is the primary beneficiary of Arcadian as it has power over the activities that most significantly impact the economic performance of Arcadian. As a result, the Company has consolidated the results of Arcadian in its condensed consolidated financial statements. The Company’s financial exposure to Arcadian is limited to its investment in Arcadian’s common shares and other financial support up to $18.0 million through an unsecured promissory note. As of March 31, 2021, Arcadian’s assets and liabilities included in the Company’s condensed consolidated balance sheets were $3.5 million and $0.5 million, respectively ( December 31, 2020 - $3.3 million and $0.6 million, respectively). Noncontrolling interests Noncontrolling interests represent the portion of equity in consolidated subsidiaries not attributable, directly or indirectly, to the Company. The following table is a reconciliation of the beginning and ending carrying amount of noncontrolling interests for the three months ended March 31, 2021: March 31, 2021 Balance, beginning of period $ 1.4 Sirius Group acquisition (1) 0.3 Net income attributable to noncontrolling interests — Contributions 0.1 Balance, end of period $ 1.8 (1) See Note 3 for additional information related to the acquisition of Sirius Group. Non-consolidated variable interest entities As a result of the acquisition of Sirius Group, the Company is a passive investor in certain third-party-managed hedge and private equity funds, some of which are VIEs. The Company is not involved in the design or establishment of these VIEs, nor does it actively participate in the management of the VIEs. The exposure to loss from these investments is limited to the carrying value of the investments at the balance sheet date. The Company calculates maximum exposure to loss to be (i) the amount invested in the debt or equity of the VIE, (ii) the notional amount of VIE assets or liabilities where the Company has also provided credit protection to the VIE with the VIE as the referenced obligation, and (iii) other commitments and guarantees to the VIE. The Company does not have any VIEs that it sponsors nor any VIEs where it has recourse to it or has provided a guarantee to the VIE interest holders. The following table presents total assets of unconsolidated VIEs in which the Company holds a variable interest, as well as the maximum exposure to loss associated with these VIEs as of March 31, 2021: March 31, 2021 Maximum Exposure to Loss Total VIE Assets On-Balance Sheet Off-Balance Sheet Total Other long-term investments (1) $ 250.3 $ 213.7 $ 5.1 $ 218.8 $ 250.3 $ 213.7 $ 5.1 $ 218.8 (1) Comprised primarily of hedge funds and private equity funds. Third Point Enhanced LP TP Enhanced Fund meets the definition of a variable interest entity principally because of the existence of disproportionate rights in the partnership compared to the obligations to absorb the expected losses and right to receive the expected residual returns of TP Enhanced Fund’s results. As of March 31, 2021, the Company and TP GP hold interests of approximately 89.1% and 10.9%, respectively, of the net asset value of TP Enhanced Fund. As a result, both entities hold significant financial interests in TP Enhanced Fund. However, TP GP controls all of the investment decision-making authority and the Company does not have the power to direct the activities which most significantly impact the economic performance of TP Enhanced Fund. As a result, the Company is not considered the primary beneficiary and does not consolidate TP Enhanced Fund. The Company’s maximum exposure to loss corresponds to the value of its investments in TP Enhanced Fund. As a result of the Company’s holding in TP Enhanced Fund and its contribution to the Company’s overall financial results, the Company includes the following summarized income statement of the TP Enhanced Fund for the three months ended March 31, 2021 and 2020, and summarized balance sheet as of March 31, 2021 and December 31, 2020. Thi s summarized income (loss) statement of TP Enhanced Fund reflects the main components of total investment income (loss) and expenses of TP Enhanced Fund. This summarized income (loss) statement is not a breakdown of the Company’s proportional investment income (loss) in TP Enhanced Fund as presented in the Company’s condensed consolidated statements of income (loss). TP Enhanced Fund summarized income (loss) statement 2021 2020 Investment income (loss) Net realized gain from securities, derivative contracts and foreign currency translations $ 148.4 $ 15.6 Net change in unrealized gain (loss) on securities, derivative contracts and foreign currency translations 71.5 (251.5) Net income (loss) from currencies 0.8 (0.3) Dividend and interest income 5.4 4.4 Other income — 0.7 Total investment income (loss) 226.1 (231.1) Expenses Management fees 4.0 3.9 Interest 1.5 2.7 Dividends on securities sold, not yet purchased 1.5 1.3 Administrative and professional fees 0.7 0.4 Other expenses 1.3 0.5 Total expenses 9.0 8.8 Net income (loss) $ 217.1 $ (239.9) The following table is a summarized balance sheet of TP Enhanced Fund as of March 31, 2021 and December 31, 2020 and reflects the underlying assets and liabilities of TP Enhanced Fund. This summarized balance sheet is not a breakdown of the Company’s proportional interests in the underlying assets and liabilities of TP Enhanced Fund. TP Enhanced Fund summarized balance sheet March 31, December 31, 2020 Assets Total investments in securities and affiliated funds $ 2,409.1 $ 2,200.9 Cash and cash equivalents 40.6 40.1 Due from brokers 144.7 124.6 Derivative assets, at fair value 53.3 37.0 Interest and dividends receivable 3.0 3.2 Other assets 2.9 3.9 Total assets $ 2,653.6 $ 2,409.7 Liabilities Accounts payable and accrued expenses $ 1.3 $ 1.0 Securities sold, not yet purchased, at fair value 351.2 183.0 Securities sold under agreement to repurchase 2.5 5.5 Due to brokers 898.3 894.0 Derivative liabilities, at fair value 13.7 23.7 Withdrawals payable to General Partner — 75.0 Interest and dividends payable 1.0 0.7 Management fee payable — 0.2 Total liabilities 1,268.0 1,183.1 Total partners' capital $ 1,385.6 $ 1,226.6

Investments in unconsolidated e

Investments in unconsolidated entities	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Investments in unconsolidated entities	6. Investments The Company’s invested assets consist of investment securities and other long-term investments held for general investment purposes. The portfolio of investment securities includes debt securities, equity securities, and other-long term investments which are all classified as trading securities. Realized and unrealized investment gains and losses on trading securities are reported in pre-tax revenues. Debt securities The following tables provide the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses), and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020: March 31, 2021 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 586.0 $ 1.9 $ (0.3) $ 7.0 $ 594.6 Residential mortgage-backed securities 390.9 0.8 (2.3) 2.8 392.2 Commercial mortgage-backed securities 124.1 0.1 (1.2) — 123.0 Corporate debt securities 551.0 4.1 (1.7) 11.2 564.6 U.S. government and government agency (1) 1,127.5 1.7 (2.1) 13.8 1,140.9 Non-U.S. government and government agency 120.3 0.1 — 0.9 121.3 U.S. states, municipalities and political subdivision 0.9 — — — 0.9 Preferred stocks 2.8 — — — 2.8 Total debt securities (2) $ 2,903.5 $ 8.7 $ (7.6) $ 35.7 $ 2,940.3 (1) The Company had $9.2 million of short positions in long duration U.S. Treasuries as of March 31, 2021. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $1,031.5 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of March 31, 2021. December 31, 2020 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 1.2 $ 0.1 $ — $ — $ 1.3 Residential mortgage-backed securities 8.1 0.6 — — 8.7 Bank debt 0.3 0.1 — — 0.4 Corporate debt securities 29.4 8.4 (0.1) — 37.7 U.S. government and government agency (1) 52.4 1.7 (0.9) — 53.2 Total debt securities (2) $ 91.4 $ 10.9 $ (1.0) $ — $ 101.3 (1) The Company had $12.0 million of short positions in long duration U.S. Treasuries as of December 31, 2020. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $50.6 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of December 31, 2020. The weighted average duration of the Company's debt securities as of March 31, 2021 was approximately 1.8 years (December 31, 2020 - 10.5 years). The following table provides the cost or amortized cost and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020 by contractual maturity. Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. March 31, 2021 December 31, 2020 Cost or Fair value Cost or Fair value Due in one year or less $ 1,189.5 $ 1,203.5 $ 50.0 $ 50.6 Due after one year through five years 449.9 460.6 2.8 3.0 Due after five years through ten years 116.5 116.8 — — Due after ten years 43.8 46.8 29.4 37.7 Mortgage-backed and asset-backed securities 1,101.0 1,109.8 9.2 10.0 Preferred stocks 2.8 2.8 — — Total debt securities $ 2,903.5 $ 2,940.3 $ 91.4 $ 101.3 The following table summarizes the ratings and fair value of debt securities held in the Company's investment portfolio as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 AAA $ 804.6 $ 53.2 AA 1,645.7 — A 239.6 9.1 BBB 164.9 37.7 Other 85.5 1.3 Total debt securities (1) $ 2,940.3 $ 101.3 (1) Credit ratings are assigned based on the following hierarchy: 1) Standard & Poor's ("S&P") and 2) Moody's Investors Service. As of March 31, 2021 , the above totals included $44.2 million of sub-prime securities. Of this total, $18.6 million was rated AAA, $13.7 million rated AA and $11.9 million rated A. As of December 31, 2020, the above totals included $8.7 million of A rated sub-prime securities. Equity securities and other long-term investments The cost or amortized cost, gross unrealized investment gains and losses, net foreign currency gains, and fair values of the Company’s equity securities and other long-term investments as of March 31, 2021 and December 31, 2020, were as follows: March 31, 2021 Cost or Gross Gross Net foreign Fair value Equity securities $ 5.8 $ — $ (0.1) $ 0.2 $ 5.9 Other long-term investments $ 432.8 $ 39.8 $ (1.0) $ 1.5 $ 473.1 December 31, 2020 Cost or Gross Gross Net foreign Fair value Other long-term investments $ 4.0 $ — $ — $ — $ 4.0 Equity securities at fair value consisted of the following as of March 31, 2021: March 31, Fixed income mutual funds $ 1.8 Common stocks 4.1 Total equity securities $ 5.9 Other long-term investments at fair value consisted of the following as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Hedge funds and private equity funds (1) $ 242.1 $ — Limited liability companies and private equity securities 231.0 4.0 Total other long-term investments $ 473.1 $ 4.0 (1) Includes $161.9 million of investments valued at NAV and $80.2 million of investments valued at Level 3. Hedge funds and private equity funds The Company holds investments in hedge funds and private equity funds, which are included in other long-term investments. As of March 31, 2021 , the Company held i nvestments in 8 hedge funds and 19 private equity funds. The largest investment in a single fund was $67.9 million as of March 31, 2021. The following table summarizes investments in hedge funds and private equity interests by investment objective and sector as of March 31, 2021: March 31, 2021 Fair value Unfunded Hedge funds Long/short multi-sector $ 29.9 $ — Distressed mortgage credit 67.9 — Private credit 23.4 — Other 1.3 — Total hedge funds 122.5 — Private equity funds Energy infrastructure & services 51.3 25.8 Multi-sector 9.3 6.5 Healthcare 24.5 4.9 Life settlement 13.1 — Manufacturing/Industrial 17.2 — Private equity secondaries 0.6 0.7 Other 3.6 1.3 Total private equity funds 119.6 39.2 Total hedge and private equity funds included in other long-term investments $ 242.1 $ 39.2 Redemption of investments in certain hedge funds is subject to restrictions including lock-up periods where no redemptions or withdrawals are allowed, restrictions on redemption frequency, and advance notice periods for redemptions. Amounts requested for redemptions remain subject to market fluctuations until the redemption effective date, which generally falls at the end of the defined redemption period. The following summarizes the March 31, 2021 fair value of hedge funds subject to restrictions on redemption frequency and advance notice period requirements for investments in active hedge funds: Notice Period Redemption Frequency 1-29 days 30-59 days 60-89 days 90-119 days 120+ days Total Quarterly $ — $ 0.6 $ 29.9 $ 67.9 $ — $ 98.4 Semi-annual — — 0.3 — — 0.3 Annual — — — 0.3 23.5 23.8 Total $ — $ 0.6 $ 30.2 $ 68.2 $ 23.5 $ 122.5 Certain of the hedge fund and private equity fund investments in which the Company is invested are no longer active and are in the process of disposing of their underlying investments. Distributions from such funds are remitted to investors as the fund's underlying investments are liquidated. As of March 31, 2021, no dis tributions were outstanding from these investments. Investments in private equity funds are generally subject to a "lock-up" period during which investors may not request a redemption. Distributions prior to the expected termination date of the fund may be limited to dividends or proceeds arising from the liquidation of the fund's underlying investments. In addition, certain private equity funds provide an option to extend the lock-up period at either the sole discretion of the fund manager or upon agreement between the fund and the investors. As of March 31, 2021, investments in private equity funds were subject to lock-up periods as follows: 1 - 3 years 3 – 5 years 5 – 10 years Total Private equity funds – expected lock-up period remaining $ 48.3 $ 29.4 $ 41.9 $ 119.6 Investment in related party investment funds The following table provides the cost and fair value of the Company's investments in related party investment funds as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Cost Fair value Cost Fair value Third Point Enhanced LP $ 883.9 $ 1,200.8 $ 891.9 $ 1,055.6 Third Point Venture Offshore Fund I LP 8.0 8.0 — — Investment in related party investment funds, at fair value $ 891.9 $ 1,208.8 $ 891.9 $ 1,055.6 Investment in Third Point Enhanced LP On August 6, 2020, SiriusPoint, Third Point Reinsurance Company Ltd. (“Third Point Re BDA”) and Third Point Reinsurance (USA) Ltd. (“Third Point Re USA”) entered into the Third Amended and Restated Exempted Limited Partnership Agreement (“2020 LPA”) of Third Point Enhanced LP (“ TP Enhanced Fund ”) which became effective on February 26, 2021, except for the amendment to the calculation of the loss recovery account which became effective on December 31, 2020. In accordance with the 2020 LPA, Third Point Advisors LLC (“TP GP”) serves as the general partner of TP Enhanced Fund . The TP Enhanced Fund investment strategy, as implemented by Third Point LLC, is intended to achieve superior risk-adjusted returns by deploying capital in both long and short investments with favorable risk/reward characteristics across select asset classes, sectors and geographies. Third Point LLC identifies investment opportunities via a bottom-up, value-oriented approach to single security analysis supplemented by a top-down view of portfolio and risk management. Third Point LLC seeks dislocations in certain areas of the capital markets or in the pricing of particular securities and supplements single security analysis with an approach to portfolio construction that includes sizing each investment based on upside/downside calculations, all with a view towards appropriately positioning and managing overall exposures. Under the 2020 LPA, the Company has the right to withdraw funds monthly from TP Enhanced Fund to meet capital adequacy requirements and to satisfy financing obligations. The Company may also withdraw its investment upon the occurrence of certain events specified in the 2020 LPA, including, to meet capital adequacy requirements, to prevent a negative credit rating, for risk management purposes or to satisfy financing obligations, subject to certain limitations on such withdrawals as specified in the 2020 LPA, and may withdraw its investment in full on the first quarter end date after the 5-year anniversary of the closing date of the acquisition of Sirius Group (i.e. March 31, 2026) and each successive two-year anniversary of such date. The Company is also entitled to withdraw funds from the TP Enhanced Fund in order to satisfy its risk management guidelines, upon prior written notice to the TP GP, in an amount not to exceed 20% of the sum of (x) the aggregate opening balances of our capital account and (y) the aggregate amount of capital contributions credited to our capital account. As of March 31, 2021, the Company had no unfunded commitments related to TP Enhanced Fund. Investment in Third Point Venture Offshore Fund I LP On March 1, 2021, Third Point Re BDA entered into the Amended and Restated Exempted Limited Partnership Agreement (“2021 Venture LPA”) of Third Point Venture Offshore Fund I LP (“TP Venture Fund”) which became effective on March 1, 2021. In accordance with the 2021 Venture LPA, Third Point Venture GP LLC (“TP Venture GP”) serves as the general partner of TP Venture Fund. The TP Venture Fund investment strategy, as implemented by Third Point LLC, is to generate attractive risk-adjusted returns through a concentrated portfolio of investments in privately-held companies, primarily in the expansion through late/pre-IPO stage. The TP Venture Fund may also invest in early stage companies. Due the nature of the fund, withdrawals are not permitted. Distributions prior to the expected termination date of the fund include, but are not limited to, dividends or proceeds arising from the liquidation of the fund's underlying investments. As of March 31, 2021, the Company had $32.0 million of unfunded commitments related to TP Venture Fund. 19. Investments in unconsolidated entities The Company’s investments in unconsolidated entities are included within other long-term investments and consist of investments in common equity securities or similar instruments, which give the Company the ability to exert significant influence over the investee's operating and financial policies ("equity method eligible unconsolidated entities"). Such investments may be accounted for under either the equity method or, alternatively, the Company may elect to account for them under the fair value option. The following table presents the components of other long-term investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Equity method eligible unconsolidated entities, at fair value $ 218.0 $ — Other unconsolidated investments, at fair value (1) 255.1 4.0 Total other long-term investments (2) $ 473.1 $ 4.0 (1) Includes other long-term investments that are not equity method eligible. (2) There w ere no investm ents accounted for using the equity method as of March 31, 2021 and December 31, 2020. The Company has elected the fair value option to account for its equity method eligible investments accounted for as part of other long-term investments for consistency of presentation with the rest of its investment portfolio. The following table presents the Company’s ownership interests in investments in equity method eligible unconsolidated entities as of March 31, 2021: Investee March 31, Instrument Held BE Reinsurance Limited 24.9 % Common shares BioVentures Investors (Offshore) IV LP 73.0 % Units Camden Partners Strategic Fund V (Cayman), LP 39.4 % Units Diamond LS I LP 15.4 % Units Gateway Fund LP 22.9 % Units Monarch 12.8 % Units New Energy Capital Infrastructure Credit Fund LP 29.8 % Units New Energy Capital Infrastructure Offshore Credit Fund LP 29.8 % Units Pie Preferred Stock (1) 9.6 % Preferred shares Pie Series B Preferred Stock (1) 6.9 % Preferred shares Pie Series C Preferred Stock (1) 0.5 % Preferred shares Quintana Energy Partners 21.8 % Units Tuckerman Capital V LP 48.3 % Units Tuckerman Capital V Co-Investment I LP 49.0 % Units (1) The Company holds investments in several financing instruments of Pie Insurance Holdings, Inc.

Earnings (loss) per share avail

Earnings (loss) per share available to Third Point Re common shareholders	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings (loss) per share available to SiriusPoint common shareholders	20. Earnings (loss) per share available to SiriusPoint common shareholders The following sets forth the computation of basic and diluted earnings (loss) per share available to SiriusPoint common shareholders for the three months ended March 31, 2021 and 2020: 2021 2020 Weighted-average number of common shares outstanding: Basic number of common shares outstanding 116,760,760 92,191,837 Dilutive effect of options 184,470 — Dilutive effect of warrants 51,650 — Dilutive effect of restricted shares with service and performance condition 1,149,461 — Diluted number of common shares outstanding 118,146,341 92,191,837 Basic earnings (loss) per common share: Net income (loss) available to SiriusPoint common shareholders $ 130.9 $ (183.6) Net income allocated to SiriusPoint participating common shareholders (6.5) — Net income (loss) allocated to SiriusPoint common shareholders $ 124.4 $ (183.6) Basic earnings (loss) per share available to SiriusPoint common shareholders $ 1.07 $ (1.99) Diluted earnings (loss) per common share: Net income (loss) available to SiriusPoint common shareholders $ 130.9 $ (183.6) Net income allocated to SiriusPoint participating common shareholders (6.5) — Net income (loss) allocated to SiriusPoint common shareholders $ 124.4 $ (183.6) Diluted earnings (loss) per share available to SiriusPoint common shareholders $ 1.05 $ (1.99) For the three months ended March 31, 2021, options of 4,120,926, warrants of 25,035,220 and Upside Rights of 10,000,000 were excluded from the computation of diluted earnings per share as the average share price for the quarter was below the exercise price or reference price for the respective security. As a result of the net loss for the three months ended March 31, 2020, dilutive options, warrants and restricted shares with service and performance conditions totaling 5,117,702 were considered anti-dilutive and were excluded from the computation of diluted loss per common share. No allocation of the net loss has been made to participating shares in the calculation of diluted net loss per common share.

Related party transactions

Related party transactions	3 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
Related party transactions	21. Related party transactions In addition to the transactions disclosed in Notes 6, 14 and 18 to these condensed consolidated financial statements, the following transactions are classified as related party transactions, as the counterparties have either a direct or indirect shareholding in the Company or the Company has an investment in such counterparty. (Re)insurance contracts Subsequent to the Sirius Group acquisition, insurance and reinsurance contracts with certain of the Company’s insurance and MGU affiliates resulted in gross written premiums of $20.2 million during the three months ended March 31, 2021. As of March 31, 2021, the Company had total receivables from affiliates of $48.3 million and no payables. Equity Commitment Letter Pursuant to the equity commitment letter by and among the Company, Third Point Opportunities Master Fund L.P. and Daniel S. Loeb, entered into on August 6, 2020, Third Point Opportunities Master Fund L.P. purchased 6,093,842 of the Company’s common shares at a price of $7.9828 per share upon closing of the Company’s acquisition of Sirius Group. Transaction Matters Letter Agreement On August 6, 2020, CM Bermuda, Sirius Group, the Company and CMIG International entered into a Transaction Matters Letter Agreement (the “Transaction Matters Agreement”), pursuant to which, among other things and subject to the terms and conditions thereof, Sirius Group agreed to pay for and reimburse CMIG International and CM Bermuda for certain legal expenses incurred in connection with the Sirius Group sales process or other discussions between CMIG International, CM Bermuda and the Sirius Group occurring on or after March 6, 2020, and the Company has agreed to assume such remaining payment obligations of Sirius Group following the closing of the acquisition of Sirius Group. The Company has also agreed to pay for the fees and expenses payable by CMIG International and CM Bermuda to its financial advisor, Goldman Sachs (Asia) L.L.C., relating to the acquisition of Sirius Group. During the three months ended March 31, 2021, the Company did not pay any legal expenses incurred by CM Bermuda and CMIG International in connection with the Transaction Matters Agreement. Management and performance fees to related parties The total management and performance fees to related parties for the three months ended March 31, 2021 and 2020 were as follows: 2021 2020 Management fees $ 4.1 $ 3.9 Performance fees 38.1 — Total management and performance fees to related parties $ 42.2 $ 3.9 Management fees Third Point Enhanced LP Effective January 1, 2019, SiriusPoint, Third Point Re BDA and Third Point Re USA entered into the Second Amended and Restated Exempted Limited Partnership Agreement (the “2019 LPA”) of TP Enhanced Fund. Pursuant to the 2019 LPA, Third Point LLC is entitled to receive monthly management fees. Management fees are charged at the TP Enhanced Fund level and are calculated based on 1.25% of the investment in TP Enhanced Fund and multiplied by an exposure multiplier computed by dividing the average daily investment exposure leverage of the TP Enhanced Fund by the average daily investment exposure leverage of the Third Point Offshore Master Fund L.P. (“Offshore Master Fund”). Third Point LLC also serves as the investment manager for the Offshore Master Fund. The 2020 LPA, effective February 26, 2021, removed the adjustment for investment exposure leverage in the management fee calculation, as previously adjusted for under the 2019 LPA. The 2020 LPA did not amend the management fee rate of 1.25% per annum. Third Point Venture Offshore Fund I LP No management fees are payable by the Company under the 2021 Venture LPA . Third Point Insurance Portfolio Solutions Effective February 26, 2021, Third Point LLC, Third Point Insurance Portfolio Solutions (“TPIPS”) and the Company entered into an Investment Management Agreement (the “TPIPS IMA”), pursuant to which TPIPS will serve as investment manager to the Company and provide investment advice with respect to the investable assets of the Company, other than assets that the Company may withdraw from time to time as working capital. The Amended and Restated Collateral Assets Investment Management Agreement was terminated at the effective date of the TPIPS IMA. Pursuant to the TPIPS IMA, the Company will pay Third Point LLC a fixed management fee, payable monthly in advance, equal to 1/12 of 0.06% of the fair value of assets managed (other than assets invested in TP Enhanced Fund). Performance fees Third Point Enhanced LP Pursuant to the 2019 LPA, TP GP receives a performance fee allocation equal to 20% of the Company’s investment income in the related party investment fund. The performance fee is included as part of “Investment in related party investment fund” on the Company’s condensed consolidated balance sheet since the fees are charged at the TP Enhanced Fund level. The performance fee is subject to a loss carryforward provision pursuant to which TP GP is required to maintain a loss recovery account, which represents the sum of all prior period net loss amounts and not subsequently offset by prior year net profit amounts, and that is allocated to future profit amounts until the loss recovery account has returned to a positive balance. Until such time, no performance fees are payable, provided that the loss recovery account balance shall be reduced proportionately to reflect any withdrawals from TP Enhanced Fund. The 2019 LPA preserves the loss carryforward attributable to our investment in TP Enhanced Fund when contributions to TP Enhanced Fund are made within nine months of certain types of withdrawals from TP Enhanced Fund. Pursuant to the 2020 LPA, the performance of certain fixed income and other investments managed by Third Point LLC were included when calculating the performance fee allocation and loss recovery account amounts under the terms of the 2019 LPA for the year ended December 31, 2020 only. There are no other changes to the performance fee calculation under the 2020 LPA. Third Point Venture Offshore Fund I LP Pursuant to the 2021 Venture LPA, TP Venture GP receives a performance fee allocation equal to 20% of the Company’s investment income in the related party investment fund. Third Point Insurance Portfolio Solutions No performance-based compensation is payable by the Company under the TPIPS IMA.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	22. Commitments and Contingencies Financing See Note 13 for additional information related to the Company’s debt obligations. Letters of credit See Note 13 for additional information related to the Company’s letter of credit facilities. Liability-classified capital instruments See Note 3 for additional information related to the contingent value consideration components of the Sirius Group acquisition. Founder and Advisor Warrants As of March 31, 2021, the Company had reserved for issuance common shares underlying warrants to purchase, in the aggregate, up to 3,494,979 common shares, to founding investors and advisors. The warrants expire on December 22, 2021, and are exercisable at a price per share of $10.00. Promissory Note On September 16, 2020, the Company entered into an Unsecured Promissory Note agreement with Arcadian, pursuant to which the Company has committed to loan up to $18.0 million. Interest shall accrue and be computed on the aggregate principal amount drawn and outstanding at a rate of 8.0% per annum. No amounts were drawn as of March 31, 2021. Litigation From time to time in the normal course of business, the Company may be involved in formal and informal dispute resolution procedures, which may include arbitration or litigation, the outcomes of which determine the rights and obligations under the Company’s reinsurance contracts and other contractual agreements. In some disputes, the Company may seek to enforce its rights under an agreement or to collect funds owed to it. In other matters, the Company may resist attempts by others to collect funds or enforce alleged rights. The Company may also be involved, from time to time in the normal course of business, in formal and informal dispute resolution procedures that do not arise from, or are not directly related to, claims activity. The Company is not currently involved in any formal or informal dispute resolution procedures that it considers to be material. Leases Subsequent to the acquisition of Sirius Group, the Company now operates in new locations with additional facilities, including the United States, Canada, Europe and Asia. The Company leases office space under various non-cancelable operating lease agreements. During the three months ended March 31, 2021 and 2020, the Company recognized operating lease expense of $1.3 million and $0.2 million, respectively, including property taxes and routine maintenance expense as well as rental expenses related to short term leases. As of March 31, 2021 and December 31, 2020, the Company had $19.8 million and $0.8 million of operating lease right-of-use assets, respectively, included in other assets accounts payable, accrued expenses and other liabilities The following table presents the lease balances within the condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Operating lease right-of-use assets $ 19.8 $ 0.8 Operating lease liabilities $ 25.5 $ 0.8 Weighted average lease term (years) 3.0 1.0 Weighted average discount rate 3.4 % 7.0 % Future minimum rental commitments as of March 31, 2021 under these leases are expected to be as follows: Future Payments Remainder of 2021 $ 8.3 2022 9.2 2023 5.7 2024 2.4 2025 and thereafter 1.3 Total future annual minimum rental payments 26.9 Less: present value discount (1.4) Total lease liability as of March 31, 2021 $ 25.5 As of March 31, 2021, the Company's future operating lease obligations that have not yet commenced are immaterial.

Significant accounting polici_2

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Written premium recognition	Effective January 1, 2021, the Company changed its accounting policy for assumed written premium recognition. Previously, the Company estimated ultimate premium written for the entire contract period and recorded this estimate at inception of the contract. For contracts where the full premium written was not estimable at inception, the Company recorded premium written for the portion of the contract period for which the amount was estimable. The Company changed its accounting policy to recognize premiums written ratably over the term of the related policy or reinsurance treaty consistent with the timing of when the ceding company has recognized the written premiums. Premiums written include amounts reported by brokers and ceding companies, supplemented by the Company's own estimates of premiums where reports have not been received. The determination of premium estimates requires a review of the Company's experience with the ceding companies, managing general underwriters, familiarity with each market, the timing of the reported information, an analysis and understanding of the characteristics of each class of business and management's judgment of the impact of various factors, including premium or loss trends, on the volume of business written and ceded to
Business combinations	The Company accounts for business combinations in accordance with Accounting Standards Codification ("ASC") Topic 805 Business Combinations , and intangible assets that arise from business combinations in accordance with ASC Topic 350 Intangibles – Goodwill and Other . The difference between the fair value of net assets acquired and the purchase price is recorded as a bargain purchase gain in other revenues in the condensed consolidated statements of income (loss).
Intangible assets	Intangible assets arising from our business acquisitions are classified as either finite or indefinite-lived intangible assets. Finite-lived intangible assets are amortized over their useful lives with the amortization expense being recognized in the condensed consolidated statements of income (loss). The amortization periods approximate the period over which the Company expects to generate future net cash inflows from the use of these assets. All of these assets are subject to impairment testing for the impairment or disposal of long-lived assets when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows. Indefinite-lived intangible assets are however not subject to amortization. The carrying values of intangible assets are reviewed for indicators of impairment at least annually. The Company initially evaluates indefinite-lived intangible assets using a qualitative approach to determine whether it is more likely than not that the fair value is greater than its carrying value. If the results of the qualitative evaluation indicate that it is more likely than not that the carrying value exceeds its fair value, the Company performs the quantitative test for impairment. If indefinite-lived intangible assets are impaired, such assets are written down to their fair values with the related expense recognized in the condensed consolidated statements of income (loss).
Liability-classified capital instruments	As part of the consideration transferred in the acquisition of Sirius Group, the Company issued various instruments that were classified as liabilities based on their terms, notably the settlement features for each and any potential adjustments to the exercise price for the warrants issued. Liability-classified capital instruments reported in the condensed consolidated balance sheets include Series A preference shares, Merger warrants, Private warrants, Upside rights and Contingent value rights. See Note 3 for additional information on each of these instruments.
Defined benefit plans	Certain SiriusPoint employees in Europe participate in defined benefit plans. The liability for the defined benefit plans that is reported on the condensed consolidated balance sheets is the current value of the defined benefit obligation at the end of the period, reduced by the fair value of the plan's assets, with adjustments for actuarial gains and losses. The defined benefit pension plan obligation is calculated annually by independent actuaries. The current value of the defined benefit obligation is determined through discounting of expected future cash flows, using interest rates determined by current market interest rates. The service costs and actuarial gains and losses on the defined benefit obligation and the fair value on the plan assets are recognized in the condensed consolidated statements of income (loss).
Deferred software costs	The Company capitalizes costs related to computer software developed for internal use during the application development stage of software development projects. These costs generally consist of certain external, payroll, and payroll-related costs. The Company begins amortization of these costs once the project is completed and ready for its intended use. Amortization is on a straight-line basis and over a useful life of three
Loan participations	Loan participations that qualify for sale accounting under the ASC Topic 860 Transfers and Servicing of Financial Assets , are carried at fair value. The fair value of loan participations is estimated using discounted cash flow analysis. The Company includes loan participations in other assets in the condensed consolidated balance sheets.
Foreign currency exchange	The U.S. dollar is the functional curre ncy for the Company’s businesses except for the Canadian reinsurance operations of Sirius America Insurance Company. T he Company invests in securities denominated in foreign currencies. Assets and liabilities recorded in these foreign currencies are translated into U.S. dollars at exchange rates in effect at the balance sheet date, and revenues and expenses are converted using the average exchange rates for the period. Net foreign exchange gains and losses arising from the translation of functional currencies are reported in shareholder's equity, in accumulated other comprehensive (loss). As of March 31, 2021, the Company had net unrealized foreign currency translation gains of $0.4 million recorded in accumulated other comprehensive income (loss) on its condensed consolidated balance sheet. Assets and liabilities relating to foreign operations are remeasured into the functional currency using current exchange rates; revenues and expenses are remeasured into the functional currency using the weighted average exchange rate for the period. The resulting exchange gains and losses are reported as a component of net income in the period in which they arise within net realized and unrealized gains (losses) and net foreign exchange gains (losses).
Recently issued accounting standards	Issued and effective as of March 31, 2021 In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). The amendments in ASU 2019-12 simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. A SU 2019-12 is effective for public business entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years . The Company has fully adopted all provisions of the guidance with consideration of the various transition methods. The Company also adopted all other provisions in the guidance, including the requirement for an entity to recognize a franchise tax (or similar tax) that is partially based on income as an income-based tax and account for any incremental amount incurred as a non-income-based tax through a cumulative-effect adjustment to retained earnings. These provisions did not have a material impact on the Company’s condensed consolidated financial statements or were not applicable to the Company. In January 2020, the FASB issued Accounting Standards Update 2020-01, Investments—Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 (a consensus of the Emerging Issues Task Force) (“ASU 2020-01”). The amendments in ASU 2020-01 clarify certain interactions between the guidance to account for certain equity securities under Topic 321, the guidance to account for investments under the equity method of accounting in Topic 323, and the guidance in Topic 815, which could change how an entity accounts for an equity security under the m easurement alternative for a forward contract or purchased option to purchase securities that, upon settlement of the forward contract or exercise of the purchased option, would be accounted for under the equity method of accounting or the fair value option in accordance with Topic 825, Financial Instruments. These amendments improve current U.S. GAAP by reducing diversity in practice and increasing comparability of the accounting for these interactions. ASU 2020-01 is effective for public business entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Adoption of ASU 2020-01 did not have a material impact on the Company’s condensed consolidated financial statements. In October 2020, the FASB issued Accounting Standards Update 2020-09, Debt (Topic 470): Amendments to SEC Paragraphs Pursuant to SEC Release No. 33-10762 (“ASU 2020-09”). The amendments in ASU 2020-09 amend and supersede SEC paragraphs in the Accounting Standards Codification to reflect the issuance of SEC Release No. 33-10762 related to financial disclosure requirements for subsidiary issuers and guarantors of registered debt securities and affiliates whose securities are pledged as collateral for registered securities. SEC Release No. 33-10762 simplifies the disclosure requirements related to certain registered securities under Rules 3-10 and 3-16 of Regulation S-X, permitting registrants to provide certain alternative financial disclosures and non-financial disclosures in lieu of separate consolidating financial statements for subsidiary issuers and guarantors of registered debt securities if certain conditions are met. The amendments in ASU 2020-09 are generally effective for filings on or after January 4, 2021, with early application permitted. The Company adopted the new disclosure requirements permitted under ASU 2020-09 effective for the quarter ended March 31, 2021. Issued but not yet effective as of March 31, 2021 Other accounting pronouncements issued during the three months ended March 31, 2021 were either not relevant to the Company or did not impact the Company’s condensed consolidated financial statements.

Significant accounting polici_3

Significant accounting policies (Tables)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Schedule of the retrospective impact from the change in accounting policy	The following tables provide a summary of the retrospective impact from the change in accounting policy on the Company’s condensed consolidated financial statements: Condensed consolidated balance sheet December 31, 2020 As previously reported Adjustment As adjusted Insurance and reinsurance balances receivable, net $ 559.4 $ (117.5) $ 441.9 Deferred acquisition costs, net and value of business acquired 134.3 (65.7) 68.6 Unearned premiums ceded 27.7 (7.2) 20.5 Total assets 3,725.6 (190.4) 3,535.2 Reinsurance balances payable 80.4 (2.3) 78.1 Unearned premium reserves 472.9 (188.1) 284.8 Total liabilities 2,160.3 (190.4) 1,969.9 Shareholders’ equity attributable to SiriusPoint common shareholders $ 1,563.9 $ — $ 1,563.9 Condensed consolidated statement of income (loss) Three months ended March 31, 2020 As previously reported Adjustment As adjusted Gross premiums written $ 204.1 $ (78.4) $ 125.7 Gross premiums ceded 0.3 (2.8) (2.5) Net premiums written 204.4 (81.2) 123.2 Change in net unearned premium reserves (58.1) 81.2 23.1 Net premiums earned $ 146.3 $ — $ 146.3 Net loss attributable to SiriusPoint common shareholders $ (183.6) $ — $ (183.6) Condensed consolidated statement of cash flows Three months ended March 31, 2020 As previously reported Adjustment As adjusted Insurance and reinsurance balances receivable $ (28.2) $ 52.9 $ 24.7 Deferred acquisition costs, net and value of business acquired (13.8) 27.0 13.2 Unearned premiums ceded 3.5 (2.8) 0.7 Unearned premium reserves 54.5 (78.4) (23.9) Reinsurance balances payable (2.5) 1.3 (1.2) Net cash used in operating activities $ (3.2) $ — $ (3.2)

Acquisition of Sirius Group (Ta

Acquisition of Sirius Group (Tables)	3 Months Ended
	Mar. 31, 2021
Business Combinations [Abstract]
Schedule of the total purchase price	The components of the Company's total purchase price for Sirius Group at February 26, 2021 were as follows: Cash consideration Sirius Group shares acquired for cash $ 100.4 Common Shares Common Shares issued by SiriusPoint 58,331,196 SiriusPoint share price as of February 26, 2021 $ 10.21 595.6 Preference Shares Series A Preference Shares issued, at fair value 40.8 Series B Preference Shares issued, at fair value (1) 200.0 Warrants Merger warrants issued, at fair value 53.4 Private warrants issued, at fair value 7.3 Upside Rights Upside Rights issued, at fair value 6.5 Contingent value rights (CVRs) CVRs issued, at fair value 27.0 CVR waiver restricted shares 0.7 Other Fair value of the replaced Sirius Group equity awards attributable to pre-combination services 37.5 Transaction fee reimbursement 8.0 Total purchase price $ 1,077.2 (1) See Note 16 for additional information.
Schedule of estimated fair values of major classes of identifiable assets acquired and liabilities assumed	The following table summarizes the estimated fair values of major classes of identifiable assets acquired and liabilities assumed of Sirius Group as of February 26, 2021, the date the transaction closed: Identifiable net assets: Cash and investments $ 3,944.1 Insurance and reinsurance balances receivable, net 1,201.0 Reinsurance assets 649.7 Value of business acquired 147.9 Deferred tax asset 230.5 Intangible assets 175.0 Other assets 181.9 Loss and loss adjustment expense reserves (2,928.5) Unearned premium reserves (900.0) Deferred tax liability (192.4) Debt (728.2) Other liabilities (695.2) Total identifiable net assets acquired 1,085.8 Total purchase price 1,077.2 Bargain purchase gain $ 8.6
Schedule of identifiable intangible assets	Identifiable intangible assets at February 26, 2021 and at March 31, 2021 , consisted of the following, and are included in intangible assets on the Company’s condensed consolidated balance sheet: Amount Economic Useful Life Distribution relationships $ 75.0 17 years MGA relationships 34.0 13 years Lloyd’s Capacity - Syndicate 1945 38.0 Indefinite Insurance licenses 7.0 Indefinite Trade name 16.0 16 years Internally developed and used computer software 5.0 5 years Identifiable intangible assets, before amortization, at February 26, 2021 175.0 Amortization (from February 26, 2021 through March 31, 2021) (0.8) Net identifiable intangible assets at March 31, 2021 related to the acquisition of Sirius Group $ 174.2
Schedule of results of Sirius Group and pro forma financial information	The following table summarizes the results of Sirius Group since February 26, 2021 that have been included in the Company's condensed consolidated statements of income: For the period from Total revenues $ 146.2 Net income $ 23.3 2021 2020 Total revenues $ 664.7 $ 390.3 Net income (loss) $ 165.8 $ (461.4)

Segment reporting (Tables)

Segment reporting (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of operating segment results	The following is a summary of the Company’s operating segment results for the three months ended March 31, 2021 and 2020: Three months ended March 31, 2021 A&H Specialty Property Runoff & Total Gross premiums written (1) $ 134.8 $ 167.7 $ 62.1 $ 2.0 $ 366.6 Net premiums written (1) 103.6 144.5 60.3 1.9 310.3 Net premiums earned (1) 35.0 139.0 80.2 1.8 256.0 Loss and loss adjustment expenses incurred, net (2) 14.0 87.1 45.4 1.6 148.1 Acquisition costs, net 5.1 42.3 21.2 0.4 69.0 Other underwriting expenses (2) 10.6 9.9 8.2 1.5 30.2 Net underwriting income (loss) $ 5.3 $ (0.3) $ 5.4 $ (1.7) 8.7 Other revenues 8.6 Net investment income 186.5 Net corporate and other expenses (68.3) Intangible asset amortization (0.8) Interest expense (4.9) Foreign exchange gains 12.4 Income before income tax expense $ 142.2 Underwriting Ratios: (3) Loss ratio 40.0 % 62.7 % 56.6 % NM 57.8 % Acquisition cost ratio 14.6 % 30.4 % 26.5 % NM 27.0 % Other underwriting expenses ratio 30.3 % 7.1 % 10.2 % NM 11.8 % Combined ratio (4) 84.9 % 100.2 % 93.3 % NM 96.6 % Three months ended March 31, 2020 A&H Specialty Property Runoff & Total Gross premiums written (1) $ 1.3 $ 79.4 $ 45.0 $ — $ 125.7 Net premiums written (1) 1.3 76.9 45.0 — 123.2 Net premiums earned (1) 1.2 99.4 45.1 0.6 146.3 Loss and loss adjustment expenses incurred, net (2) 1.0 67.4 18.1 1.3 87.8 Acquisition costs, net 0.2 33.5 16.0 (0.4) 49.3 Other underwriting expenses (2) — 4.5 1.5 1.2 7.2 Net underwriting income (loss) $ — $ (6.0) $ 9.5 $ (1.5) 2.0 Net investment loss (185.0) Net corporate and other expenses (6.4) Interest expense (2.0) Foreign exchange gains 8.2 Loss before income tax expense $ (183.2) Underwriting Ratios: (3) Loss ratio 83.3 % 67.8 % 40.1 % NM 60.0 % Acquisition cost ratio 16.7 % 33.7 % 35.5 % NM 33.7 % Other underwriting expenses ratio — % 4.5 % 3.3 % NM 4.9 % Combined ratio (4) 100.0 % 106.0 % 78.9 % NM 98.6 % (1) Includes service fee revenue from the Company’s MGUs of $10.8 million for the three months ended March 31, 2021 (2020 - $nil). (2) Loss and loss adjustment expenses incurred, net and other underwriting expenses include expenses associated with the Company’s MGUs of $1.0 million and $7.3 million, respectively, for the three months ended March 31, 2021 (2020 - $nil). (3) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (4) Ratios considered not meaningful ("NM") to Runoff & Other. (5) The Company modified the presentation of its operating segments in the three months ended March 31, 2021 to better align with the manner in which

Cash, cash equivalents, restr_2

Cash, cash equivalents, restricted cash and restricted investments (Tables)	3 Months Ended
	Mar. 31, 2021
Cash and Cash Equivalents [Abstract]
Schedule of restrictions on cash and cash equivalents and investments	The following table provides a summary of cash and cash equivalents, restricted cash and restricted investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Cash and cash equivalents $ 932.4 $ 526.0 Restricted cash securing letter of credit facilities (1) 463.6 306.0 Restricted cash securing reinsurance contracts (2) 929.7 881.9 Restricted cash held by managing general underwriters 18.0 — Total cash, cash equivalents and restricted cash (3) 2,343.7 1,713.9 Restricted investments securing reinsurance contracts (2) 1,084.5 86.4 Total cash, cash equivalents, restricted cash and restricted investments $ 3,428.2 $ 1,800.3 (1) Restricted cash securing letter of credit facilities primarily pertains to letters of credit that have been issued to the Company’s clients in support of our obligations under reinsurance contracts. The Company will not be released from the obligation to provide these letters of credit until the reserves underlying the reinsurance contracts have been settled. The time period for which the Company expects each letter of credit to be in place varies from contract to contract but can last several years. (2) Restricted cash and restricted investments securing reinsurance contracts pertain to trust accounts securing the Company’s contractual obligations under certain reinsurance contracts that the Company will not be released from until the underlying risks have expired or have been settled. Restricted investments include certain investments in debt securities and limited partnership interests in Third Point Enhanced LP. The time period for which the Company expects these trust accounts to be in place varies from contract to contract, but can last several years. (3) Cash, cash equivalents and restricted cash as reported in the Company’s condensed consolidated statements of cash flows.
Schedule of cash and cash equivalents	The following table provides a summary of cash and cash equivalents, restricted cash and restricted investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Cash and cash equivalents $ 932.4 $ 526.0 Restricted cash securing letter of credit facilities (1) 463.6 306.0 Restricted cash securing reinsurance contracts (2) 929.7 881.9 Restricted cash held by managing general underwriters 18.0 — Total cash, cash equivalents and restricted cash (3) 2,343.7 1,713.9 Restricted investments securing reinsurance contracts (2) 1,084.5 86.4 Total cash, cash equivalents, restricted cash and restricted investments $ 3,428.2 $ 1,800.3 (1) Restricted cash securing letter of credit facilities primarily pertains to letters of credit that have been issued to the Company’s clients in support of our obligations under reinsurance contracts. The Company will not be released from the obligation to provide these letters of credit until the reserves underlying the reinsurance contracts have been settled. The time period for which the Company expects each letter of credit to be in place varies from contract to contract but can last several years. (2) Restricted cash and restricted investments securing reinsurance contracts pertain to trust accounts securing the Company’s contractual obligations under certain reinsurance contracts that the Company will not be released from until the underlying risks have expired or have been settled. Restricted investments include certain investments in debt securities and limited partnership interests in Third Point Enhanced LP. The time period for which the Company expects these trust accounts to be in place varies from contract to contract, but can last several years. (3) Cash, cash equivalents and restricted cash as reported in the Company’s condensed consolidated statements of cash flows.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of debt securities	The following tables provide the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency gains (losses), and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020: March 31, 2021 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 586.0 $ 1.9 $ (0.3) $ 7.0 $ 594.6 Residential mortgage-backed securities 390.9 0.8 (2.3) 2.8 392.2 Commercial mortgage-backed securities 124.1 0.1 (1.2) — 123.0 Corporate debt securities 551.0 4.1 (1.7) 11.2 564.6 U.S. government and government agency (1) 1,127.5 1.7 (2.1) 13.8 1,140.9 Non-U.S. government and government agency 120.3 0.1 — 0.9 121.3 U.S. states, municipalities and political subdivision 0.9 — — — 0.9 Preferred stocks 2.8 — — — 2.8 Total debt securities (2) $ 2,903.5 $ 8.7 $ (7.6) $ 35.7 $ 2,940.3 (1) The Company had $9.2 million of short positions in long duration U.S. Treasuries as of March 31, 2021. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $1,031.5 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of March 31, 2021. December 31, 2020 Cost or Gross Gross Net foreign Fair value Asset-backed securities $ 1.2 $ 0.1 $ — $ — $ 1.3 Residential mortgage-backed securities 8.1 0.6 — — 8.7 Bank debt 0.3 0.1 — — 0.4 Corporate debt securities 29.4 8.4 (0.1) — 37.7 U.S. government and government agency (1) 52.4 1.7 (0.9) — 53.2 Total debt securities (2) $ 91.4 $ 10.9 $ (1.0) $ — $ 101.3 (1) The Company had $12.0 million of short positions in long duration U.S. Treasuries as of December 31, 2020. These amounts are included in securities sold, not yet purchased in the condensed consolidated balance sheets. (2) Included in total debt securities are $50.6 million of investments in highly liquid securities with maturities greater than three months but less than one year from the date of purchase as of December 31, 2020.
Schedule of debt securities by contractual maturity	The following table provides the cost or amortized cost and fair value of the Company's debt securities as of March 31, 2021 and December 31, 2020 by contractual maturity. Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. March 31, 2021 December 31, 2020 Cost or Fair value Cost or Fair value Due in one year or less $ 1,189.5 $ 1,203.5 $ 50.0 $ 50.6 Due after one year through five years 449.9 460.6 2.8 3.0 Due after five years through ten years 116.5 116.8 — — Due after ten years 43.8 46.8 29.4 37.7 Mortgage-backed and asset-backed securities 1,101.0 1,109.8 9.2 10.0 Preferred stocks 2.8 2.8 — — Total debt securities $ 2,903.5 $ 2,940.3 $ 91.4 $ 101.3
Schedule of the ratings and fair value of debt securities	The following table summarizes the ratings and fair value of debt securities held in the Company's investment portfolio as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 AAA $ 804.6 $ 53.2 AA 1,645.7 — A 239.6 9.1 BBB 164.9 37.7 Other 85.5 1.3 Total debt securities (1) $ 2,940.3 $ 101.3 (1) Credit ratings are assigned based on the following hierarchy: 1) Standard & Poor's ("S&P") and 2) Moody's Investors Service.
Schedule of equity securities and other long-term investments	The cost or amortized cost, gross unrealized investment gains and losses, net foreign currency gains, and fair values of the Company’s equity securities and other long-term investments as of March 31, 2021 and December 31, 2020, were as follows: March 31, 2021 Cost or Gross Gross Net foreign Fair value Equity securities $ 5.8 $ — $ (0.1) $ 0.2 $ 5.9 Other long-term investments $ 432.8 $ 39.8 $ (1.0) $ 1.5 $ 473.1 December 31, 2020 Cost or Gross Gross Net foreign Fair value Other long-term investments $ 4.0 $ — $ — $ — $ 4.0 Equity securities at fair value consisted of the following as of March 31, 2021: March 31, Fixed income mutual funds $ 1.8 Common stocks 4.1 Total equity securities $ 5.9 Other long-term investments at fair value consisted of the following as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Hedge funds and private equity funds (1) $ 242.1 $ — Limited liability companies and private equity securities 231.0 4.0 Total other long-term investments $ 473.1 $ 4.0 (1) Includes $161.9 million of investments valued at NAV and $80.2 million of investments valued at Level 3.
Schedule of investments in hedge funds and private equity interests by investment objective and sector	The following table summarizes investments in hedge funds and private equity interests by investment objective and sector as of March 31, 2021: March 31, 2021 Fair value Unfunded Hedge funds Long/short multi-sector $ 29.9 $ — Distressed mortgage credit 67.9 — Private credit 23.4 — Other 1.3 — Total hedge funds 122.5 — Private equity funds Energy infrastructure & services 51.3 25.8 Multi-sector 9.3 6.5 Healthcare 24.5 4.9 Life settlement 13.1 — Manufacturing/Industrial 17.2 — Private equity secondaries 0.6 0.7 Other 3.6 1.3 Total private equity funds 119.6 39.2 Total hedge and private equity funds included in other long-term investments $ 242.1 $ 39.2
Schedule of other long-term investments subject to restrictions	The following summarizes the March 31, 2021 fair value of hedge funds subject to restrictions on redemption frequency and advance notice period requirements for investments in active hedge funds: Notice Period Redemption Frequency 1-29 days 30-59 days 60-89 days 90-119 days 120+ days Total Quarterly $ — $ 0.6 $ 29.9 $ 67.9 $ — $ 98.4 Semi-annual — — 0.3 — — 0.3 Annual — — — 0.3 23.5 23.8 Total $ — $ 0.6 $ 30.2 $ 68.2 $ 23.5 $ 122.5 As of March 31, 2021, investments in private equity funds were subject to lock-up periods as follows: 1 - 3 years 3 – 5 years 5 – 10 years Total Private equity funds – expected lock-up period remaining $ 48.3 $ 29.4 $ 41.9 $ 119.6
Schedule of investments in related party investment funds	The following table provides the cost and fair value of the Company's investments in related party investment funds as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Cost Fair value Cost Fair value Third Point Enhanced LP $ 883.9 $ 1,200.8 $ 891.9 $ 1,055.6 Third Point Venture Offshore Fund I LP 8.0 8.0 — — Investment in related party investment funds, at fair value $ 891.9 $ 1,208.8 $ 891.9 $ 1,055.6

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of investments, categorized by the level of the fair value hierarchy	The following tables present the Company’s investments, categorized by the level of the fair value hierarchy as of March 31, 2021 and December 31, 2020: March 31, 2021 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 594.6 $ — $ 594.6 Residential mortgage-backed securities — 392.2 — 392.2 Commercial mortgage-backed securities — 123.0 — 123.0 Corporate debt securities — 564.6 — 564.6 U.S. government and government agency 1,076.3 64.6 — 1,140.9 Non-U.S. government and government agency 24.9 96.4 — 121.3 U.S. states, municipalities and political subdivision — 0.9 — 0.9 Preferred stocks — — 2.8 2.8 Total debt securities 1,101.2 1,836.3 2.8 2,940.3 Fixed income mutual funds 1.8 — — 1.8 Common stocks 4.1 — — 4.1 Total equity securities 5.9 — — 5.9 Other long-term investments — — 311.2 311.2 Derivative assets 1.6 — 3.2 4.8 Loan participation — — 32.8 32.8 $ 1,108.7 $ 1,836.3 $ 350.0 3,295.0 Investments in funds valued at NAV 1,370.7 Total assets $ 4,665.7 Liabilities U.S. Government and government agency $ — $ 9.2 $ — $ 9.2 Total securities sold, not yet purchased — 9.2 — 9.2 Liability-classified capital instruments — — 135.0 135.0 Contingent consideration — — 1.5 1.5 Derivative liabilities — — 3.5 3.5 Total liabilities $ — $ 9.2 $ 140.0 $ 149.2 December 31, 2020 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 1.3 $ — $ 1.3 Residential mortgage-backed securities — 8.7 — 8.7 Bank debt — 0.4 — 0.4 Corporate debt securities — 37.7 — 37.7 U.S. Government and government agency — 53.2 — 53.2 Total debt securities — 101.3 — 101.3 Other long-term investments — — 4.0 4.0 Derivative assets — — 1.2 1.2 $ — $ 101.3 $ 5.2 106.5 Investments in funds valued at NAV 1,055.6 Total assets $ 1,162.1 Liabilities U.S. Government and government agency $ — $ 12.0 $ — $ 12.0 Total securities sold, not yet purchased — 12.0 — 12.0 Derivative liabilities — — 1.0 1.0 Total liabilities $ — $ 12.0 $ 1.0 $ 13.0
Reconciliation of assets measured at fair value using Level 3 inputs	The following table presents the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2021 and 2020: January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired (1) Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Preferred stocks $ — $ — $ — $ 2.8 $ — $ — $ 2.8 Other long-term investments 4.0 — 13.6 259.0 (1.0) 35.6 311.2 Derivative assets 1.2 — — 0.3 — 1.7 3.2 Loan participation — — — 32.8 — — 32.8 Total assets $ 5.2 $ — $ 13.6 $ 294.9 $ (1.0) $ 37.3 $ 350.0 Liabilities Liability-classified capital instruments $ — $ — $ (135.0) $ — $ — $ — $ (135.0) Contingent consideration — — — (0.7) — (0.8) (1.5) Derivative liabilities (1.0) — — (2.0) — (0.5) (3.5) Total liabilities $ (1.0) $ — $ (135.0) $ (2.7) $ — $ (1.3) $ (140.0) January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Asset-backed securities $ — $ — $ 4.4 $ — $ — $ — $ 4.4 Other long-term investments 4.0 — — — — — 4.0 Total assets $ 4.0 $ — $ 4.4 $ — $ — $ — $ 8.4 Liabilities Derivative liabilities $ — $ — $ — $ — $ — $ — $ — Total liabilities $ — $ — $ — $ — $ — $ — $ — (1) Includes amounts acquired as a result of the Sirius Group acquisition. (2) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in net investment income (loss) in the condensed consolidated statements of income (loss). Realized and unrealized gains (losses) related to underwriting-related derivative assets and liabilities are included in other underwriting expenses, net of foreign exchange (gains) losses, in the condensed consolidated statements of income (loss).
Reconciliation of liabilities measured at fair value using Level 3 inputs	The following table presents the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2021 and 2020: January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired (1) Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Preferred stocks $ — $ — $ — $ 2.8 $ — $ — $ 2.8 Other long-term investments 4.0 — 13.6 259.0 (1.0) 35.6 311.2 Derivative assets 1.2 — — 0.3 — 1.7 3.2 Loan participation — — — 32.8 — — 32.8 Total assets $ 5.2 $ — $ 13.6 $ 294.9 $ (1.0) $ 37.3 $ 350.0 Liabilities Liability-classified capital instruments $ — $ — $ (135.0) $ — $ — $ — $ (135.0) Contingent consideration — — — (0.7) — (0.8) (1.5) Derivative liabilities (1.0) — — (2.0) — (0.5) (3.5) Total liabilities $ (1.0) $ — $ (135.0) $ (2.7) $ — $ (1.3) $ (140.0) January 1, Transfers in to (out of) Level 3 Purchases Assets Acquired Sales Realized and Unrealized Gains (Losses) (2) March 31, Assets Asset-backed securities $ — $ — $ 4.4 $ — $ — $ — $ 4.4 Other long-term investments 4.0 — — — — — 4.0 Total assets $ 4.0 $ — $ 4.4 $ — $ — $ — $ 8.4 Liabilities Derivative liabilities $ — $ — $ — $ — $ — $ — $ — Total liabilities $ — $ — $ — $ — $ — $ — $ — (1) Includes amounts acquired as a result of the Sirius Group acquisition. (2) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in net investment income (loss) in the condensed consolidated statements of income (loss). Realized and unrealized gains (losses) related to underwriting-related derivative assets and liabilities are included in other underwriting expenses, net of foreign exchange (gains) losses, in the condensed consolidated statements of income (loss).
Schedule of significant unobservable inputs used for recurring fair value measurements for certain Level 3 instruments	The table below presents information about the significant unobservable inputs used for recurring fair value measurements for certain Level 3 instruments as of March 31, 2021, and includes only those instruments for which information about the inputs is reasonably available to the Company, such as data from independent third-party valuation service providers and from internal valuation models. March 31, 2021 Assets (Liability) Fair Value Valuation Technique Unobservable input Private equity securities (4) $ 152.0 Subject company transaction approach Share price range 19.84 - 23.34 Private equity funds (3) 80.2 Net asset value discount Discount range 50% - 95% Private equity securities (1) 39.6 Share price of recent transaction Purchase share price 50.79 Loan participations (5) 32.8 Share price of recent transaction Comparable yields Range - 4.91%-7.82% Median - 5.92% Private equity securities (1) 15.0 Multiple of GAAP book value Book value multiple Range - 0.73x-0.91x Median - 0.82x Common Stock (1) 10.0 Purchase price of recent transaction Purchase price 10.0 Private debt instrument (1) 6.5 Discounted cash flow Discount yield Range - 6.55%-7.03% Median - 6.73% Preferred stock (1) 3.0 Purchase price of recent transaction Purchase price 3.0 Preferred stocks (5) 2.8 Share price of recent transaction Share price 2.8 Promissory note (1) 2.5 Purchase price of recent transaction Purchase price 2.5 Preferred stock (1) 1.1 Purchase price of recent transaction Purchase price 1.1 Membership Interest (1) 1.0 Purchase price of recent transaction Purchase price 1.0 Equity warrants (2) 0.3 Option pricing model Strike price 0.2 Private equity securities (1) 0.3 Purchase price of recent transaction Purchase price 0.3 Weather derivatives (2) (0.3) Third party appraisal Broker quotes (0.3) Contingent consideration (1) (1.5) External valuation model Discounted future payments (1.5) Currency swaps (2) (2.2) Third party appraisal Broker quotes (2.2) Upside rights (1) (6.5) External valuation model Share price (6.5) Private warrants (1) (7.3) Black Scholes pricing model Share price 1.81 Contingent value rights (1) (27.0) External valuation model Share price 5.91 Series A preference shares (1) (40.8) External valuation model Share price (40.8) Merger warrants (1) $ (53.4) External valuation model Share price 2.54 (1) Each asset type consists of one security except as indicated below. (2) See Note 8 for discussion of derivative instruments. (3) Represents multiple private equity funds where a discount on net asset value was taken. (4) Represents various tranches of the Company's investment in Pie. (5) Represents multiple securities held under the same Investment Management Agreement.
Schedule of financial instruments for which the carrying value differs from the estimated fair values	The following table includes financial instruments for which the carrying value differs from the estimated fair values at March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Fair Value Carrying Value Fair Value Carrying Value 2017 SEK Subordinated Notes (1) $ 307.2 $ 307.9 n/a n/a 2016 SIG Senior Notes (1) 405.0 406.8 n/a n/a 2015 TPRUSA Senior Notes (2) $ 117.5 $ 114.3 $ 117.8 $ 114.3 (1) These financial instruments are not actively traded. Fair value is estimated by internal pricing and therefore considered a Level 3 measurement. (2) Fair value based on observable inputs and considered a Level 2 measurement.

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of derivative instruments	The following table summarizes information on the classification and amount of the fair value of derivatives not designated as hedging instruments within the Company's condensed consolidated balance sheets as at March 31, 2021: March 31, 2021 Derivatives not designated as hedging instruments Notional Value Derivative assets at fair value (1) Derivative liabilities at fair value (2) Interest rate cap (3) $ 250.0 $ — $ — Foreign currency swaps 40.0 — 2.3 Weather derivatives 31.2 — 0.2 Foreign currency futures contracts (3) 100.8 — — Foreign currency call options 50.6 1.6 — Equity warrants $ 0.3 $ 0.3 $ — (1) Derivative assets are classified within other assets in the Company's condensed consolidated balance sheets at March 31, 2021. (2) Derivative liabilities are classified within accounts payable, accrued expenses and other liabilities in the Company's condensed consolidated balance sheets at March 31, 2021. (3) De minimis as of March 31, 2021. (4) The Company did not hold the above derivative instruments as of December 31, 2020. The following tables identify the listing currency, fair value and notional amounts of underwriting-related derivatives included in the condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Derivative assets Listing currency (1) Fair Value Notional Amounts (2) Fair Value Notional Amounts (2) Reinsurance contracts accounted for as derivative assets GBP $ 2.9 $ 2.9 $ 1.2 $ 4.2 $ 2.9 $ 2.9 $ 1.2 $ 4.2 March 31, 2021 December 31, 2020 Derivative liabilities Listing currency (1) Fair Value Notional Amounts (2) Fair Value Notional Amounts (2) Reinsurance contracts accounted for as derivative liabilities GBP $ 1.0 $ 13.4 $ 1.0 $ 15.7 $ 1.0 $ 13.4 $ 1.0 $ 15.7 (1) GBP = British Pound. (2) The absolute notional exposure represents the Company’s derivative activity as of March 31, 2021 and December 31, 2020, which is representative of the volume of derivatives held during the period.
Schedule of net impact on earnings relating to derivatives	The following table summarizes information on the classification and net impact on earnings, recognized in the Company's condensed consolidated statements of income (loss) relating to derivatives during the three months ended March 31, 2021: Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings 2021 Foreign currency swaps Foreign exchange gains $ (0.4) Weather derivatives Net corporate and other expenses (0.1) Foreign currency futures contracts Foreign exchange gains (3.7) Foreign currency call options Foreign exchange gains $ (1.6)

Loss and loss adjustment expe_2

Loss and loss adjustment expense reserves (Tables)	3 Months Ended
	Mar. 31, 2021
Insurance [Abstract]
Schedule of loss and loss adjustment expense reserves	The following table represents the activity in the loss and loss adjustment expense reserves for the three months ended March 31, 2021 and 2020: 2021 2020 Gross reserves for loss and loss adjustment expenses, beginning of period $ 1,310.1 $ 1,111.7 Less: loss and loss adjustment expenses recoverable, beginning of period (14.4) (5.5) Less: deferred charges on retroactive reinsurance contracts (6.0) (6.7) Net reserves for loss and loss adjustment expenses, beginning of period 1,289.7 1,099.5 Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in: Current year 147.7 92.2 Prior years 0.4 (4.4) Total incurred loss and loss adjustment expenses 148.1 87.8 Net loss and loss adjustment expenses paid in respect of losses occurring in: Current year (15.9) (10.1) Prior years (117.2) (74.0) Total net paid losses (133.1) (84.1) Foreign currency translation (10.6) (10.2) Amounts acquired as a result of Sirius Group acquisition (1) 2,467.8 — Net reserves for loss and loss adjustment expenses, end of period 3,761.9 1,093.0 Plus: loss and loss adjustment expenses recoverable, end of period 492.6 6.9 Plus: deferred charges on retroactive reinsurance contracts (2) 4.8 8.0 Gross reserves for loss and loss adjustment expenses, end of period $ 4,259.3 $ 1,107.9 (1) Represents the fair value of Sirius Group’s reserves for claims and claim expenses, net of reinsurance recoverables, acquired at February 26, 2021. See Note 3 for additional information related to the acquisition of Sirius Group. (2) Deferred charges on retroactive contracts are recorded in other assets on the Company’s condensed consolidated balance sheets.

Allowance for expected credit_2

Allowance for expected credit losses (Tables)	3 Months Ended
	Mar. 31, 2021
Receivables [Abstract]
Schedule of assets in scope of the current expected credit losses assessment	The Company's assets in scope of the current expected credit loss assessment as of March 31, 2021 and December 31, 2020 are as follows: March 31, December 31, 2020 Insurance and reinsurance balances receivable, net $ 1,613.8 $ 441.9 Loss and loss adjustment expenses recoverable, net 492.6 14.4 Other assets (1) 15.9 — Total assets in scope $ 2,122.3 $ 456.3 (1) Relates to MGU trade receivables included in other assets in the Company’s condensed consolidated balance sheets.

Deposit contracts (Tables)

Deposit contracts (Tables)	3 Months Ended
	Mar. 31, 2021
Insurance [Abstract]
Schedule of activity for deposit contracts	The following table represents activity for the deposit contracts for the three months ended March 31, 2021 and year ended December 31, 2020: March 31, December 31, 2020 Balance, beginning of period $ 153.0 $ 172.3 Consideration received 0.4 0.5 Net investment expense allocation 0.8 0.9 Payments (3.4) (20.8) Foreign currency translation (0.1) 0.1 Balance, end of period $ 150.7 $ 153.0

Debt and letter of credit fac_2

Debt and letter of credit facilities (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of debt obligations	The following table represents a summar y of the Company’s debt obl igations on its condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, 2021 December 31, 2020 Amount Effective rate (1) Amount Effective rate (1) 2017 SEK Subordinated Notes, at face value (2) $ 315.1 4.1 % n/a n/a Unamortized discount (7.2) n/a 2017 SEK Subordinated Notes, carrying value 307.9 n/a 2016 SIG Senior Notes, at face value 400.0 4.5 % n/a n/a Unamortized premium 6.8 n/a 2016 SIG Senior Notes, carrying value (2) 406.8 n/a 2015 TPRUSA Senior Notes, at face value 115.0 7.0 % 115.0 7.0 % Unamortized issuance costs (0.7) (0.7) 2015 TPRUSA Senior Notes, carrying value 114.3 114.3 Total debt $ 829.0 $ 114.3 (1) Effective rate considers the effect of the debt issuance costs, discount, and premium.
Schedule of letter of credit facilities	As of March 31, 2021, the Company had entered into the following letter of credit facilities: Letters of Credit Collateral Committed Capacity Issued Cash and Cash Equivalents Debt securities Committed - Secured letters of credit facilities $ 2,026.0 $ 1,089.5 $ 168.2 $ 751.8 Uncommitted - Secured letters of credit facilities n/a 296.1 295.4 — $ 1,385.6 $ 463.6 $ 751.8

Net investment income (loss) (T

Net investment income (loss) (Tables)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of net investment income (loss)	Net investment income (loss) for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ (7.8) $ 19.7 Equity securities 0.3 — Other long-term investments 49.2 — Net investment income (loss) from investments in related party investment funds 153.2 (200.8) Net investment income (loss) before other investment expenses and investment loss on cash and cash equivalents 194.9 (181.1) Other investment expenses (1.0) (0.2) Net investment loss on cash and cash equivalents (7.4) (3.7) Net investment income (loss) $ 186.5 $ (185.0)
Schedule of net realized investment gains	Net realized and unrealized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Gross realized gains $ 19.3 $ 2.7 Gross realized losses (0.4) (1.7) Net realized gains on investments (1) 18.9 1.0 Net unrealized gains on investments (2) 12.6 10.6 Net realized and unrealized gains on investments (3) $ 31.5 $ 11.6 (1) Includes realized gains (losses) due to foreign currency of $2.1 million for the three months ended March 31, 2021 (2020 - $(0.1) million). (2) Includes unrealized losses due to foreign currency of $(16.3) million for the three months ended March 31, 2021 (2020 - $(8.6) million). (3) Excludes realized and unrealized gains (losses) on the Company’s investments in related party investment funds. Net realized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ 6.3 $ (0.7) Equity securities 0.4 — Other long-term investments 9.9 — Net investment income on cash and cash equivalents 2.3 1.7 Net realized investment gains $ 18.9 $ 1.0
Schedule of net unrealized investment gains	Net realized and unrealized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Gross realized gains $ 19.3 $ 2.7 Gross realized losses (0.4) (1.7) Net realized gains on investments (1) 18.9 1.0 Net unrealized gains on investments (2) 12.6 10.6 Net realized and unrealized gains on investments (3) $ 31.5 $ 11.6 (1) Includes realized gains (losses) due to foreign currency of $2.1 million for the three months ended March 31, 2021 (2020 - $(0.1) million). (2) Includes unrealized losses due to foreign currency of $(16.3) million for the three months ended March 31, 2021 (2020 - $(8.6) million). (3) Excludes realized and unrealized gains (losses) on the Company’s investments in related party investment funds. Net unrealized investment gains for the three months ended March 31, 2021 and 2020 consisted of the following: 2021 2020 Debt securities $ (16.9) $ 19.4 Equity securities (0.1) — Other long-term investments 39.3 — Net investment loss on cash and cash equivalents (9.7) (8.8) Net unrealized investment gains $ 12.6 $ 10.6 The following table summarizes the amount of total gains included in earnings attributable to unrealized investment gains – Level 3 investments for the three months ended March 31, 2021 and 2020: 2021 2020 Other long-term investments $ 35.6 $ — Total unrealized investment gains – Level 3 investments $ 35.6 $ —

Shareholders' equity (Tables)

Shareholders' equity (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Schedule of common shares issued and outstanding	The following table presents a summary of the common shares issued and outstanding as of and for the three months ended March 31, 2021 and 2020: 2021 2020 Common shares issued, beginning of period 95,582,733 94,225,498 Issuance of common shares, net of forfeitures and shares withheld 2,081,001 283,008 Performance restricted shares granted, net of forfeitures and shares withheld (197,418) 372,723 Issuance of common shares for Sirius Group acquisition 58,331,196 — Issuance of common shares to related party 6,093,842 — Common shares issued, end of period 161,891,354 94,881,229

Share-based compensation (Table

Share-based compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of share-based compensation expense	The following table provides the total share-based compensation expense included in general and administrative expenses during the three months ended March 31, 2021 and 2020: 2021 2020 Restricted shares with service condition $ 2.0 $ 0.5 Restricted shares with service and performance condition 0.3 1.1 $ 2.3 $ 1.6
Schedule of management and director options activity	The options activity for the three months ended March 31, 2021 was as follows: Number of Weighted average Balance as of January 1, 2021 8,255,810 13.45 Granted 2,183,853 10.78 Balance as of March 31, 2021 10,439,663 12.89
Schedule of information management and director options outstanding and exercisable	The following table summarizes information about the Company’s management and director share options outstanding and exercisable as of March 31, 2021: Options outstanding Options exercisable Range of exercise prices Number of Weighted average Remaining contractual life Number of Weighted average $9.83 - $10.89 6,528,039 $ 9.98 0.6 years 6,528,039 $ 9.98 $15.00 - $16.89 2,190,696 15.75 2.7 years 1,790,696 15.92 $20.00 - $25.05 1,720,928 20.28 1.0 years 1,720,928 20.28 10,439,663 $ 12.89 1.1 years 10,039,663 $ 11.06
Schedule of restricted share award activity	Restricted share award activity for the three months ended March 31, 2021 and year ended December 31, 2020 was as follows: Number of non- Weighted Balance as of January 1, 2020 340,767 $ 11.83 Granted 1,029,373 8.30 Forfeited (16,434) 9.77 Vested (182,648) 10.10 Balance as of January 1, 2021 1,171,058 8.80 Granted 1,188,380 10.21 Vested (204,864) 9.89 Balance as of March 31, 2021 2,154,574 $ 9.47
Schedule of RSU activity	RSU activity for the three months ended March 31, 2021 was as follows: Number of non- Weighted Balance as of January 1, 2021 — $ — Granted 4,935,144 10.21 Vested (2,051,730) 10.21 Balance as of March 31, 2021 2,883,414 10.21
Schedule of restricted share activity with a service and performance condition	Restricted share award activity for the restricted shares with a service and performance condition for the three months ended March 31, 2021 and year ended December 31, 2020 were as follows: Number of non- Number of non- Weighted average grant date fair value of shares probable of vesting Balance as of January 1, 2020 1,890,529 1,314,036 $ 12.43 Granted 749,322 499,542 9.46 Forfeited (372,476) (39,214) 12.12 Vested (504,440) (504,440) 12.16 Change in estimated restricted shares considered probable of vesting n/a 132,656 11.28 Balance as of January 1, 2021 1,762,935 1,402,580 10.98 Forfeited (166,702) — 14.03 Vested (300,469) (300,469) 14.03 Change in estimated restricted shares considered probable of vesting n/a (238,279) 10.33 Balance as of March 31, 2021 1,295,764 863,832 $ 10.11

Variable interest entities (Tab

Variable interest entities (Tables)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of noncontrolling interests	Noncontrolling interests represent the portion of equity in consolidated subsidiaries not attributable, directly or indirectly, to the Company. The following table is a reconciliation of the beginning and ending carrying amount of noncontrolling interests for the three months ended March 31, 2021: March 31, 2021 Balance, beginning of period $ 1.4 Sirius Group acquisition (1) 0.3 Net income attributable to noncontrolling interests — Contributions 0.1 Balance, end of period $ 1.8 (1) See Note 3 for additional information related to the acquisition of Sirius Group.
Schedule of information related to unconsolidated variable interest entities	The following table presents total assets of unconsolidated VIEs in which the Company holds a variable interest, as well as the maximum exposure to loss associated with these VIEs as of March 31, 2021: March 31, 2021 Maximum Exposure to Loss Total VIE Assets On-Balance Sheet Off-Balance Sheet Total Other long-term investments (1) $ 250.3 $ 213.7 $ 5.1 $ 218.8 $ 250.3 $ 213.7 $ 5.1 $ 218.8 (1) Comprised primarily of hedge funds and private equity funds. Thi s summarized income (loss) statement of TP Enhanced Fund reflects the main components of total investment income (loss) and expenses of TP Enhanced Fund. This summarized income (loss) statement is not a breakdown of the Company’s proportional investment income (loss) in TP Enhanced Fund as presented in the Company’s condensed consolidated statements of income (loss). TP Enhanced Fund summarized income (loss) statement 2021 2020 Investment income (loss) Net realized gain from securities, derivative contracts and foreign currency translations $ 148.4 $ 15.6 Net change in unrealized gain (loss) on securities, derivative contracts and foreign currency translations 71.5 (251.5) Net income (loss) from currencies 0.8 (0.3) Dividend and interest income 5.4 4.4 Other income — 0.7 Total investment income (loss) 226.1 (231.1) Expenses Management fees 4.0 3.9 Interest 1.5 2.7 Dividends on securities sold, not yet purchased 1.5 1.3 Administrative and professional fees 0.7 0.4 Other expenses 1.3 0.5 Total expenses 9.0 8.8 Net income (loss) $ 217.1 $ (239.9) The following table is a summarized balance sheet of TP Enhanced Fund as of March 31, 2021 and December 31, 2020 and reflects the underlying assets and liabilities of TP Enhanced Fund. This summarized balance sheet is not a breakdown of the Company’s proportional interests in the underlying assets and liabilities of TP Enhanced Fund. TP Enhanced Fund summarized balance sheet March 31, December 31, 2020 Assets Total investments in securities and affiliated funds $ 2,409.1 $ 2,200.9 Cash and cash equivalents 40.6 40.1 Due from brokers 144.7 124.6 Derivative assets, at fair value 53.3 37.0 Interest and dividends receivable 3.0 3.2 Other assets 2.9 3.9 Total assets $ 2,653.6 $ 2,409.7 Liabilities Accounts payable and accrued expenses $ 1.3 $ 1.0 Securities sold, not yet purchased, at fair value 351.2 183.0 Securities sold under agreement to repurchase 2.5 5.5 Due to brokers 898.3 894.0 Derivative liabilities, at fair value 13.7 23.7 Withdrawals payable to General Partner — 75.0 Interest and dividends payable 1.0 0.7 Management fee payable — 0.2 Total liabilities 1,268.0 1,183.1 Total partners' capital $ 1,385.6 $ 1,226.6

Investments in unconsolidated_2

Investments in unconsolidated entities (Tables)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of other long-term investments	The following table presents the components of other long-term investments as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Equity method eligible unconsolidated entities, at fair value $ 218.0 $ — Other unconsolidated investments, at fair value (1) 255.1 4.0 Total other long-term investments (2) $ 473.1 $ 4.0 (1) Includes other long-term investments that are not equity method eligible. (2) There w ere no investm ents accounted for using the equity method as of March 31, 2021 and December 31, 2020.
Schedule of ownership interest in equity method eligible unconsolidated entities	The following table presents the Company’s ownership interests in investments in equity method eligible unconsolidated entities as of March 31, 2021: Investee March 31, Instrument Held BE Reinsurance Limited 24.9 % Common shares BioVentures Investors (Offshore) IV LP 73.0 % Units Camden Partners Strategic Fund V (Cayman), LP 39.4 % Units Diamond LS I LP 15.4 % Units Gateway Fund LP 22.9 % Units Monarch 12.8 % Units New Energy Capital Infrastructure Credit Fund LP 29.8 % Units New Energy Capital Infrastructure Offshore Credit Fund LP 29.8 % Units Pie Preferred Stock (1) 9.6 % Preferred shares Pie Series B Preferred Stock (1) 6.9 % Preferred shares Pie Series C Preferred Stock (1) 0.5 % Preferred shares Quintana Energy Partners 21.8 % Units Tuckerman Capital V LP 48.3 % Units Tuckerman Capital V Co-Investment I LP 49.0 % Units (1) The Company holds investments in several financing instruments of Pie Insurance Holdings, Inc.

Earnings (loss) per share ava_2

Earnings (loss) per share available to SiriusPoint common shareholders (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Computation of basic and diluted earnings (loss) per share available to SiriusPoint common shareholders	The following sets forth the computation of basic and diluted earnings (loss) per share available to SiriusPoint common shareholders for the three months ended March 31, 2021 and 2020: 2021 2020 Weighted-average number of common shares outstanding: Basic number of common shares outstanding 116,760,760 92,191,837 Dilutive effect of options 184,470 — Dilutive effect of warrants 51,650 — Dilutive effect of restricted shares with service and performance condition 1,149,461 — Diluted number of common shares outstanding 118,146,341 92,191,837 Basic earnings (loss) per common share: Net income (loss) available to SiriusPoint common shareholders $ 130.9 $ (183.6) Net income allocated to SiriusPoint participating common shareholders (6.5) — Net income (loss) allocated to SiriusPoint common shareholders $ 124.4 $ (183.6) Basic earnings (loss) per share available to SiriusPoint common shareholders $ 1.07 $ (1.99) Diluted earnings (loss) per common share: Net income (loss) available to SiriusPoint common shareholders $ 130.9 $ (183.6) Net income allocated to SiriusPoint participating common shareholders (6.5) — Net income (loss) allocated to SiriusPoint common shareholders $ 124.4 $ (183.6) Diluted earnings (loss) per share available to SiriusPoint common shareholders $ 1.05 $ (1.99)

Related party transactions (Tab

Related party transactions (Tables)	3 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
Schedule of management and performance fees to related parties	The total management and performance fees to related parties for the three months ended March 31, 2021 and 2020 were as follows: 2021 2020 Management fees $ 4.1 $ 3.9 Performance fees 38.1 — Total management and performance fees to related parties $ 42.2 $ 3.9

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of lease balances	The following table presents the lease balances within the condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020: March 31, December 31, 2020 Operating lease right-of-use assets $ 19.8 $ 0.8 Operating lease liabilities $ 25.5 $ 0.8 Weighted average lease term (years) 3.0 1.0 Weighted average discount rate 3.4 % 7.0 %
Schedule of future minimum rental commitments	Future minimum rental commitments as of March 31, 2021 under these leases are expected to be as follows: Future Payments Remainder of 2021 $ 8.3 2022 9.2 2023 5.7 2024 2.4 2025 and thereafter 1.3 Total future annual minimum rental payments 26.9 Less: present value discount (1.4) Total lease liability as of March 31, 2021 $ 25.5

Significant accounting polici_4

Significant accounting policies - Summary of the retrospective impact of change in accounting policy (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Condensed consolidated balance sheet
Insurance and reinsurance balances receivable, net	$ 1,613.8		$ 441.9
Deferred acquisition costs, net and value of business acquired	218.8		68.6
Unearned premiums ceded	247.7		20.5
Total assets	10,169.7		3,535.2
Reinsurance balances payable	528.8		78.1
Unearned premium reserves	1,244.8		284.8
Total liabilities	7,560.4		1,969.9
Shareholders’ equity attributable to SiriusPoint common shareholders	2,607.5		1,563.9
Condensed consolidated statement of income (loss)
Gross premiums written		$ 125.7
Gross premiums ceded	(56.3)	(2.5)
Net premiums written	310.3	123.2
Change in net unearned premium reserves		23.1
Net premiums earned	256	146.3
Net loss attributable to SiriusPoint common shareholders	124.4	(183.6)
Condensed consolidated statement of cash flows
Insurance and reinsurance balances receivable	29	24.7
Deferred acquisition costs, net and value of business acquired	(2.3)	13.2
Unearned premiums ceded	(38.2)	0.7
Unearned premium reserves	60	(23.9)
Reinsurance balances payable	62.7	(1.2)
Net cash used in operating activities	$ (48.8)	(3.2)
As previously reported
Condensed consolidated balance sheet
Insurance and reinsurance balances receivable, net			559.4
Deferred acquisition costs, net and value of business acquired			134.3
Unearned premiums ceded			27.7
Total assets			3,725.6
Reinsurance balances payable			80.4
Unearned premium reserves			472.9
Total liabilities			2,160.3
Shareholders’ equity attributable to SiriusPoint common shareholders			1,563.9
Condensed consolidated statement of income (loss)
Gross premiums written		204.1
Gross premiums ceded		0.3
Net premiums written		204.4
Change in net unearned premium reserves		(58.1)
Net premiums earned		146.3
Net loss attributable to SiriusPoint common shareholders		(183.6)
Condensed consolidated statement of cash flows
Insurance and reinsurance balances receivable		(28.2)
Deferred acquisition costs, net and value of business acquired		(13.8)
Unearned premiums ceded		3.5
Unearned premium reserves		54.5
Reinsurance balances payable		(2.5)
Net cash used in operating activities		(3.2)
Adjustment
Condensed consolidated balance sheet
Insurance and reinsurance balances receivable, net			(117.5)
Deferred acquisition costs, net and value of business acquired			(65.7)
Unearned premiums ceded			(7.2)
Total assets			(190.4)
Reinsurance balances payable			(2.3)
Unearned premium reserves			(188.1)
Total liabilities			(190.4)
Shareholders’ equity attributable to SiriusPoint common shareholders			$ 0
Condensed consolidated statement of income (loss)
Gross premiums written		(78.4)
Gross premiums ceded		(2.8)
Net premiums written		(81.2)
Change in net unearned premium reserves		81.2
Net premiums earned		0
Net loss attributable to SiriusPoint common shareholders		0
Condensed consolidated statement of cash flows
Insurance and reinsurance balances receivable		52.9
Deferred acquisition costs, net and value of business acquired		27
Unearned premiums ceded		(2.8)
Unearned premium reserves		(78.4)
Reinsurance balances payable		1.3
Net cash used in operating activities		$ 0

Significant accounting polici_5

Significant accounting policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	$ 0.4	$ 0
Minimum | Deferred software costs
Finite-Lived Intangible Assets [Line Items]
Useful life	3 years
Maximum | Deferred software costs
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years
Net unrealized foreign currency translation gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income	$ 0.4

Acquisition of Sirius Group - N

Acquisition of Sirius Group - Narrative (Details)	Feb. 26, 2021USD ($)$ / sharesshares	Aug. 06, 2020	Mar. 31, 2021USD ($)$ / sharesshares	Feb. 25, 2021$ / sharesshares
Business Acquisition [Line Items]
Common shares, par value (in dollars per share) | $ / shares			$ 0.10
Number of consecutive trading days	30 days
Affiliated entity
Business Acquisition [Line Items]
Consideration received	$ 48,600,000
Maximum percentage of shares committed to purchase		9.50%
Sirius Group
Business Acquisition [Line Items]
Cash consideration	100,400,000
Loss and loss adjustment expense reserves, casualty liability adjustment	70,000,000
Finite lived intangible assets recognized	130,000,000
Indefinite lived intangible assets recognized	$ 45,000,000
Sirius Group | Common shares
Business Acquisition [Line Items]
Shares issued (in shares) | shares	58,331,196
Value of shares issued	$ 595,600,000
Sirius Group | Contingent value rights
Business Acquisition [Line Items]
Contingent cash payment per share contributor (in dollars per share) | $ / shares	$ 13.73
Settlement calculation, number of consecutive trading days	14 days
Value of shares issued	$ 27,000,000
Settlement calculation, multiplier	0.743
Sirius Group | Series A preference shares
Business Acquisition [Line Items]
Shares issued (in shares) | shares	11,720,987
Value of shares issued	$ 40,800,000
Par value (in dollars per share) | $ / shares	$ 0.10
Dividends paid to preference shareholders			$ 0
TPRE Net COVID Loss threshold	$ 51,100,000
Sirius Net COVID Loss threshold	150,000,000
TPRE Net COVID Loss	0
Sirius Net COVID Loss	0
Numerator for shares forfeiture calculation where the Sirius Net COVID Loss is greater than the TPRE Net COVID Loss, maximum amount	$ 100,000,000
Denominator for shares forfeiture calculation where the Sirius Net COVID Loss is greater than the TPRE Net COVID Loss, number of business days	30 days
Denominator for shares forfeiture calculation where the TPRE Net COVID Loss is greater than the Sirius Net COVID Loss, number of trading days	30 days
Convertible preferred stock, shares issued upon conversion (in shares) | shares	1
Sirius Group | Merger warrants
Business Acquisition [Line Items]
Value of shares issued	$ 53,400,000
Number of shares permitted to purchase per warrant (in shares) | shares	1
Warrant exercise price (in dollars per share) | $ / shares	$ 11
Warrants, term	5 years
Number of shares in which the warrants can be converted (in shares) | shares			21,009,324
Sirius Group | Private warrants
Business Acquisition [Line Items]
Value of shares issued	$ 7,300,000
Warrant exercise price (in dollars per share) | $ / shares	$ 13
Minimum equity and cash value per share (in dollars per share) | $ / shares	$ 13.73
Sirius Group | Upside rights
Business Acquisition [Line Items]
Value of shares issued	$ 6,500,000
Target share price (in dollars per share) | $ / shares	$ 20
Numerator for settlement calculation, common shares value	$ 100,070,726
Denominator for settlement calculation, number of days	30 days
Sirius Group | Consideration Option One
Business Acquisition [Line Items]
Cash paid per acquiree share (in dollars per share) | $ / shares	$ 9.50
Sirius Group | Consideration Option Two
Business Acquisition [Line Items]
Common shares, par value (in dollars per share) | $ / shares	$ 0.10
Sirius Group | Consideration Option Two | Common shares
Business Acquisition [Line Items]
Entity shares issued per acquiree share (in shares) | shares	0.743
Sirius Group | Consideration Option Two | Contingent value rights
Business Acquisition [Line Items]
Entity shares issued per acquiree share (in shares) | shares	1
Contingent cash payment per share contributor (in dollars per share) | $ / shares	$ 13.73
Contingent cash payment, threshold share price (in dollars per share) | $ / shares	$ 18.50
Settlement calculation, number of consecutive trading days	14 days
Shares issued (in shares) | shares	4,700,000
Sirius Group | Consideration Option Three
Business Acquisition [Line Items]
Cash paid per acquiree share (in dollars per share) | $ / shares	$ 0.905
Entity principal amount of shares issued per acquiree share	$ 0.905
Sirius Group | Consideration Option Three | Common shares
Business Acquisition [Line Items]
Entity shares issued per acquiree share (in shares) | shares	0.496
Sirius Group | Consideration Option Three | Series A preference shares
Business Acquisition [Line Items]
Entity shares issued per acquiree share (in shares) | shares	0.106
Preference shares, par value (in dollars per share) | $ / shares	$ 0.10
Sirius Group | Consideration Option Three | Merger warrants
Business Acquisition [Line Items]
Entity shares issued per acquiree share (in shares) | shares	0.190
Sirius Group
Business Acquisition [Line Items]
Common shares, par value (in dollars per share) | $ / shares				$ 0.01
Sirius Group | Public warrants
Business Acquisition [Line Items]
Warrant exercise price (in dollars per share) | $ / shares	$ 18.89
Sirius Group | Private warrants
Business Acquisition [Line Items]
Number of shares in which the warrants can be converted (in shares) | shares				5,418,434

Acquisition of Sirius Group - P

Acquisition of Sirius Group - Purchase price calculation (Details) - Sirius Group $ / shares in Units, $ in Millions	Feb. 26, 2021USD ($)$ / sharesshares
Business Acquisition [Line Items]
Sirius Group shares acquired for cash	$ 100.4
Fair value of the replaced Sirius Group equity awards attributable to pre-combination services	37.5
Transaction fee reimbursement	8
Total purchase price	$ 1,077.2
Common shares
Business Acquisition [Line Items]
Common Shares issued by SiriusPoint (in shares) | shares	58,331,196
SiriusPoint share price as of February 26, 2021 (in dollars per share) | $ / shares	$ 10.21
Equity interests issued	$ 595.6
Series A preference shares
Business Acquisition [Line Items]
Common Shares issued by SiriusPoint (in shares) | shares	11,720,987
Equity interests issued	$ 40.8
Series B preference shares
Business Acquisition [Line Items]
Equity interests issued	200
Merger warrants
Business Acquisition [Line Items]
Equity interests issued	53.4
Private warrants
Business Acquisition [Line Items]
Equity interests issued	7.3
Upside rights
Business Acquisition [Line Items]
Equity interests issued	6.5
CVRs
Business Acquisition [Line Items]
Equity interests issued	27
CVR waiver restricted shares
Business Acquisition [Line Items]
Equity interests issued	$ 0.7

Acquisition of Sirius Group - F

Acquisition of Sirius Group - Fair value of net assets acquired and liabilities assumed (Details) - USD ($) $ in Millions	Feb. 26, 2021	Mar. 31, 2021	Mar. 31, 2020
Business Acquisition [Line Items]
Bargain purchase gain		$ 8.6	$ 0
Sirius Group
Business Acquisition [Line Items]
Cash and investments	$ 3,944.1
Insurance and reinsurance balances receivable, net	1,201
Reinsurance assets	649.7
Value of business acquired	147.9
Deferred tax asset	230.5
Intangible assets	175
Other assets	181.9
Loss and loss adjustment expense reserves	(2,928.5)
Unearned premium reserves	(900)
Deferred tax liability	(192.4)
Debt	(728.2)
Other liabilities	(695.2)
Total identifiable net assets acquired	1,085.8
Total purchase price	1,077.2
Bargain purchase gain	$ 8.6

Acquisition of Sirius Group - I

Acquisition of Sirius Group - Identifiable intangible assets (Details) - USD ($) $ in Millions	Feb. 26, 2021	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2020
Business Acquisition [Line Items]
Amortization (from February 26, 2021 through March 31, 2021)			$ (0.8)	$ 0
Sirius Group
Business Acquisition [Line Items]
Finite lived intangible assets recognized	$ 130
Indefinite lived intangible assets recognized	45
Identifiable intangible assets, before amortization, at February 26, 2021	175
Amortization (from February 26, 2021 through March 31, 2021)		$ (0.8)
Net identifiable intangible assets at March 31, 2021 related to the acquisition of Sirius Group		$ 174.2	$ 174.2
Sirius Group | LLoyd's Capacity - Syndicate 1945
Business Acquisition [Line Items]
Indefinite lived intangible assets recognized	38
Sirius Group | Insurance licenses
Business Acquisition [Line Items]
Indefinite lived intangible assets recognized	7
Sirius Group | Distribution relationships
Business Acquisition [Line Items]
Finite lived intangible assets recognized	$ 75
Economic Useful Life	17 years
Sirius Group | MGA relationships
Business Acquisition [Line Items]
Finite lived intangible assets recognized	$ 34
Economic Useful Life	13 years
Sirius Group | Trade name
Business Acquisition [Line Items]
Finite lived intangible assets recognized	$ 16
Economic Useful Life	16 years
Sirius Group | Internally developed and used computer software
Business Acquisition [Line Items]
Finite lived intangible assets recognized	$ 5
Economic Useful Life	5 years

Acquisition of Sirius Group -_2

Acquisition of Sirius Group - Financial results included in the condensed consolidated statements of income (Details) - Sirius Group $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Business Acquisition [Line Items]
Total revenues	$ 146.2
Net income	$ 23.3

Acquisition of Sirius Group - S

Acquisition of Sirius Group - Supplemental pro forma information (Details) - Sirius Group - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Business Acquisition [Line Items]
Total revenues	$ 664.7	$ 390.3
Net income (loss)	$ 165.8	$ (461.4)

Segment reporting - Narrative (

Segment reporting - Narrative (Details)	3 Months Ended
	Mar. 31, 2021productsegment
Segment Reporting Information [Line Items]
Number of operating segments | segment	4
Specialty | Credit | Minimum
Segment Reporting Information [Line Items]
Credit and bond reinsurance, coverage period	60 days
Specialty | Credit | Maximum
Segment Reporting Information [Line Items]
Credit and bond reinsurance, coverage period	120 days
Specialty | Environmental
Segment Reporting Information [Line Items]
Number of core products | product	4

Segment reporting - Operating s

Segment reporting - Operating segment results (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Gross premiums written	$ 366,600,000	$ 125,700,000
Net premiums written	310,300,000	123,200,000
Net premiums earned	256,000,000	146,300,000
Loss and loss adjustment expenses incurred, net	148,100,000	87,800,000
Acquisition costs, net	69,000,000	49,300,000
Other underwriting expenses	30,200,000	7,200,000
Net underwriting income (loss)	8,700,000	2,000,000
Other revenues	8,600,000	0
Net investment income (loss)	186,500,000	(185,000,000)
Net corporate and other expenses	(68,300,000)	(6,400,000)
Intangible asset amortization	(800,000)	0
Interest expense	(4,900,000)	(2,000,000)
Foreign exchange gains	12,400,000	8,200,000
Income before income tax (expense) benefit	$ 142,200,000	$ (183,200,000)
Underwriting Ratios:
Loss ratio	57.80%	60.00%
Acquisition cost ratio	27.00%	33.70%
Other underwriting expenses ratio	11.80%	4.90%
Combined ratio	96.60%	98.60%
Subsidiaries
Segment Reporting Information [Line Items]
Gross premiums written	$ 10,800,000	$ 0
Net premiums written	10,800,000	0
Net premiums earned	10,800,000	0
Loss and loss adjustment expenses incurred, net	1,000,000	0
Other underwriting expenses	7,300,000	0
A&H
Segment Reporting Information [Line Items]
Gross premiums written	134,800,000	1,300,000
Net premiums written	103,600,000	1,300,000
Net premiums earned	35,000,000	1,200,000
Loss and loss adjustment expenses incurred, net	14,000,000	1,000,000
Acquisition costs, net	5,100,000	200,000
Other underwriting expenses	10,600,000	0
Net underwriting income (loss)	$ 5,300,000	$ 0
Underwriting Ratios:
Loss ratio	40.00%	83.30%
Acquisition cost ratio	14.60%	16.70%
Other underwriting expenses ratio	30.30%	0.00%
Combined ratio	84.90%	100.00%
Specialty
Segment Reporting Information [Line Items]
Gross premiums written	$ 167,700,000	$ 79,400,000
Net premiums written	144,500,000	76,900,000
Net premiums earned	139,000,000	99,400,000
Loss and loss adjustment expenses incurred, net	87,100,000	67,400,000
Acquisition costs, net	42,300,000	33,500,000
Other underwriting expenses	9,900,000	4,500,000
Net underwriting income (loss)	$ (300,000)	$ (6,000,000)
Underwriting Ratios:
Loss ratio	62.70%	67.80%
Acquisition cost ratio	30.40%	33.70%
Other underwriting expenses ratio	7.10%	4.50%
Combined ratio	100.20%	106.00%
Property
Segment Reporting Information [Line Items]
Gross premiums written	$ 62,100,000	$ 45,000,000
Net premiums written	60,300,000	45,000,000
Net premiums earned	80,200,000	45,100,000
Loss and loss adjustment expenses incurred, net	45,400,000	18,100,000
Acquisition costs, net	21,200,000	16,000,000
Other underwriting expenses	8,200,000	1,500,000
Net underwriting income (loss)	$ 5,400,000	$ 9,500,000
Underwriting Ratios:
Loss ratio	56.60%	40.10%
Acquisition cost ratio	26.50%	35.50%
Other underwriting expenses ratio	10.20%	3.30%
Combined ratio	93.30%	78.90%
Runoff & Other
Segment Reporting Information [Line Items]
Gross premiums written	$ 2,000,000	$ 0
Net premiums written	1,900,000	0
Net premiums earned	1,800,000	600,000
Loss and loss adjustment expenses incurred, net	1,600,000	1,300,000
Acquisition costs, net	400,000	(400,000)
Other underwriting expenses	1,500,000	1,200,000
Net underwriting income (loss)	$ (1,700,000)	$ (1,500,000)

Cash, cash equivalents, restr_3

Cash, cash equivalents, restricted cash and restricted investments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 932.4	$ 526
Restricted cash	1,411.3	1,187.9
Total cash, cash equivalents and restricted cash	2,343.7	1,713.9	$ 1,420.9	$ 1,654
Restricted investments securing reinsurance contracts	1,084.5	86.4
Total cash, cash equivalents, restricted cash and restricted investments	3,428.2	1,800.3
Managing general underwriters
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	18	0
Letter of credit facilities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	463.6	306
Reinsurance contracts
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 929.7	$ 881.9

Investments - Summary of debt s

Investments - Summary of debt securities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	$ 2,903.5	$ 91.4
Gross unrealized gains	8.7	10.9
Gross unrealized (losses)	(7.6)	(1)
Net foreign currency gains (losses)	35.7	0
Fair value	2,940.3	101.3
Securities sold, not yet purchased, at fair value	9.2	12
Asset-backed securities
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	586	1.2
Gross unrealized gains	1.9	0.1
Gross unrealized (losses)	(0.3)	0
Net foreign currency gains (losses)	7	0
Fair value	594.6	1.3
Residential mortgage-backed securities
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	390.9	8.1
Gross unrealized gains	0.8	0.6
Gross unrealized (losses)	(2.3)	0
Net foreign currency gains (losses)	2.8	0
Fair value	392.2	8.7
Commercial mortgage-backed securities
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	124.1
Gross unrealized gains	0.1
Gross unrealized (losses)	(1.2)
Net foreign currency gains (losses)	0
Fair value	123
Bank debt
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities		0.3
Gross unrealized gains		0.1
Gross unrealized (losses)		0
Net foreign currency gains (losses)		0
Fair value		0.4
Corporate debt securities
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	551	29.4
Gross unrealized gains	4.1	8.4
Gross unrealized (losses)	(1.7)	(0.1)
Net foreign currency gains (losses)	11.2	0
Fair value	564.6	37.7
U.S. government and government agency
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	1,127.5	52.4
Gross unrealized gains	1.7	1.7
Gross unrealized (losses)	(2.1)	(0.9)
Net foreign currency gains (losses)	13.8	0
Fair value	1,140.9	53.2
Securities sold, not yet purchased, at fair value	9.2	12
Non-U.S. government and government agency
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	120.3
Gross unrealized gains	0.1
Gross unrealized (losses)	0
Net foreign currency gains (losses)	0.9
Fair value	121.3
U.S. states, municipalities and political subdivision
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	0.9
Gross unrealized gains	0
Gross unrealized (losses)	0
Net foreign currency gains (losses)	0
Fair value	0.9
Preferred stocks
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	2.8
Gross unrealized gains	0
Gross unrealized (losses)	0
Net foreign currency gains (losses)	0
Fair value	2.8
U.S. Treasuries
Debt and Equity Securities, FV-NI [Line Items]
Securities sold, not yet purchased, at fair value	9.2	12
Highly liquid securities
Debt and Equity Securities, FV-NI [Line Items]
Total debt securities	$ 1,031.5	$ 50.6

Investments - Debt securities b

Investments - Debt securities by contractual maturity (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Cost or amortized cost
Due in one year or less	$ 1,189.5	$ 50
Due after one year through five years	449.9	2.8
Due after five years through ten years	116.5	0
Due after ten years	43.8	29.4
Total debt securities	2,903.5	91.4
Fair value
Due in one year or less	1,203.5	50.6
Due after one year through five years	460.6	3
Due after five years through ten years	116.8	0
Due after ten years	46.8	37.7
Total debt securities (2)	2,940.3	101.3
Mortgage-backed and asset-backed securities
Cost or amortized cost
Debt securities without single maturity date	1,101	9.2
Fair value
Debt securities without single maturity date	1,109.8	10
Preferred stocks
Cost or amortized cost
Debt securities without single maturity date	2.8	0
Total debt securities	2.8
Fair value
Debt securities without single maturity date	2.8	$ 0
Total debt securities (2)	$ 2.8

Investments - Ratings and fair

Investments - Ratings and fair value of debt securities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	$ 2,940.3	$ 101.3
AAA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	804.6	53.2
AA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	1,645.7	0
A
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	239.6	9.1
BBB
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	164.9	37.7
Other
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading	$ 85.5	$ 1.3

Investments - Narrative (Detail

Investments - Narrative (Details)	Aug. 06, 2020	Mar. 31, 2021USD ($)fund	Dec. 31, 2020USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Weighted average duration of debt securities		1 year 9 months 18 days	10 years 6 months
Debt securities, trading		$ 2,940,300,000	$ 101,300,000
Total other long-term investments		473,100,000	4,000,000
Third Point Enhanced LP
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Unfunded commitments		0
Eligible withdrawal period after the closing date	5 years
Eligible withdrawal period at each successive anniversary of the closing date	2 years
Eligible withdrawal threshold, percentage of aggregate opening balance and aggregate capital contributions	20.00%
Third Point Venture Offshore Fund I LP
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Unfunded commitments		$ 32,000,000
Hedge funds
Debt and Equity Securities, FV-NI [Line Items]
Number of funds held as investments | fund		8
Total other long-term investments		$ 122,500,000
Other long-term investments, Unfunded commitments		$ 0
Private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Number of funds held as investments | fund		19
Total other long-term investments		$ 119,600,000
Other long-term investments, Unfunded commitments		39,200,000
Largest investment in a single fund
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments		67,900,000
AAA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		804,600,000	53,200,000
AA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		1,645,700,000	0
A
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		239,600,000	9,100,000
Sub-prime
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		44,200,000
Sub-prime | AAA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		18,600,000
Sub-prime | AA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		13,700,000
Sub-prime | A
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading		$ 11,900,000	$ 8,700,000

Investments - Summary of equity

Investments - Summary of equity securities and other long-term investments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Equity securities, Cost or amortized cost	$ 5.8
Equity securities, Gross unrealized gains	0
Equity securities, Gross unrealized (losses)	(0.1)
Equity securities, Net foreign currency gains	0.2
Equity securities, Fair value	5.9	$ 0
Other long-term investments, Cost or amortized cost	432.8	4
Other long-term investments, Gross unrealized gains	39.8	0
Other long-term investments, Gross unrealized (losses)	(1)	0
Other long-term investments, net foreign currency gains	1.5	0
Other long-term investments, Fair value	$ 473.1	$ 4

Investments - Equity securities

Investments - Equity securities and other-long term investments at fair value (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	$ 5.9	$ 0
Total other long-term investments	473.1	4
Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	0
Total other long-term investments	311.2	4
Fixed income mutual funds
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	1.8
Fixed income mutual funds | Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	0
Common stocks
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	4.1
Common stocks | Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Total equity securities	0
Hedge funds and private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	242.1	0
Hedge funds and private equity funds | Valued at NAV
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	161.9
Hedge funds and private equity funds | Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	80.2
Limited liability companies and private equity securities
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	$ 231	$ 4

Investments - Investments in he

Investments - Investments in hedge funds and private equity interests by investment objective and sector (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	$ 473.1	$ 4
Hedge funds and private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	242.1	$ 0
Investments in related investment party funds, Unfunded commitments	39.2
Total hedge funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	122.5
Investments in related investment party funds, Unfunded commitments	0
Long/short multi-sector
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	29.9
Investments in related investment party funds, Unfunded commitments	0
Distressed mortgage credit
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	67.9
Investments in related investment party funds, Unfunded commitments	0
Private credit
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	23.4
Investments in related investment party funds, Unfunded commitments	0
Other
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	1.3
Investments in related investment party funds, Unfunded commitments	0
Total private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	119.6
Investments in related investment party funds, Unfunded commitments	39.2
Energy infrastructure & services
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	51.3
Investments in related investment party funds, Unfunded commitments	25.8
Multi-sector
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	9.3
Investments in related investment party funds, Unfunded commitments	6.5
Healthcare
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	24.5
Investments in related investment party funds, Unfunded commitments	4.9
Life settlement
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	13.1
Investments in related investment party funds, Unfunded commitments	0
Manufacturing/Industrial
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	17.2
Investments in related investment party funds, Unfunded commitments	0
Private equity secondaries
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.6
Investments in related investment party funds, Unfunded commitments	0.7
Other
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	3.6
Investments in related investment party funds, Unfunded commitments	$ 1.3

Investments - Hedge funds with

Investments - Hedge funds with redemption restrictions and advance notice period requirements (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	$ 473.1	$ 4
Hedge funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	122.5
Hedge funds | 1-29 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | 30-59 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.6
Hedge funds | 60-89 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	30.2
Hedge funds | 90-119 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	68.2
Hedge funds | 120+ days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	23.5
Hedge funds | Quarterly
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	98.4
Hedge funds | Quarterly | 1-29 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Quarterly | 30-59 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.6
Hedge funds | Quarterly | 60-89 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	29.9
Hedge funds | Quarterly | 90-119 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	67.9
Hedge funds | Quarterly | 120+ days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Semi-annual
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.3
Hedge funds | Semi-annual | 1-29 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Semi-annual | 30-59 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Semi-annual | 60-89 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.3
Hedge funds | Semi-annual | 90-119 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Semi-annual | 120+ days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Annual
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	23.8
Hedge funds | Annual | 1-29 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Annual | 30-59 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Annual | 60-89 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0
Hedge funds | Annual | 90-119 days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	0.3
Hedge funds | Annual | 120+ days notice
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	$ 23.5

Investments - Private equity fu

Investments - Private equity funds subject to lock-up periods (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	$ 473.1	$ 4
Private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	119.6
Private equity funds | 1 - 3 years
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	48.3
Private equity funds | 3 – 5 years
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	29.4
Private equity funds | 5 – 10 years
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments, Fair value	$ 41.9

Investments - Investment in rel

Investments - Investment in related party investment funds (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, Cost	$ 891.9	$ 891.9
Investment in related party investment funds, Fair value	1,208.8	1,055.6
Third Point Enhanced LP
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, Cost	883.9	891.9
Investment in related party investment funds, Fair value	1,200.8	1,055.6
Third Point Venture Offshore Fund I LP
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, Cost	8	0
Investment in related party investment funds, Fair value	$ 8	$ 0

Fair Value Measurements - Inves

Fair Value Measurements - Investments categorized by the level of the fair value hierarchy (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Assets
Debt securities, trading	$ 2,940.3	$ 101.3
Total equity securities	5.9	0
Total other long-term investments	473.1	4
Total assets	4,665.7	1,162.1
Liabilities
Total securities sold, not yet purchased	9.2	12
Liability-classified capital instruments	135	0
Contingent consideration	1.5
Derivative liabilities	3.5	1
Total liabilities	149.2	13
Asset-backed securities
Assets
Debt securities, trading	594.6	1.3
Residential mortgage-backed securities
Assets
Debt securities, trading	392.2	8.7
Commercial mortgage-backed securities
Assets
Debt securities, trading	123
Bank debt
Assets
Debt securities, trading		0.4
Corporate debt securities
Assets
Debt securities, trading	564.6	37.7
U.S. government and government agency
Assets
Debt securities, trading	1,140.9	53.2
Liabilities
Total securities sold, not yet purchased	9.2	12
Non-U.S. government and government agency
Assets
Debt securities, trading	121.3
U.S. states, municipalities and political subdivision
Assets
Debt securities, trading	0.9
Preferred stocks
Assets
Debt securities, trading	2.8
Fixed income mutual funds
Assets
Total equity securities	1.8
Common stocks
Assets
Total equity securities	4.1
Fair Value, Inputs, Level 1, 2 and 3
Assets
Debt securities, trading	2,940.3	101.3
Total equity securities	5.9
Total other long-term investments	311.2	4
Derivative assets	4.8	1.2
Loan participation	32.8
Total assets	3,295	106.5
Fair Value, Inputs, Level 1, 2 and 3 | Asset-backed securities
Assets
Debt securities, trading	594.6	1.3
Fair Value, Inputs, Level 1, 2 and 3 | Residential mortgage-backed securities
Assets
Debt securities, trading	392.2	8.7
Fair Value, Inputs, Level 1, 2 and 3 | Commercial mortgage-backed securities
Assets
Debt securities, trading	123
Fair Value, Inputs, Level 1, 2 and 3 | Bank debt
Assets
Debt securities, trading		0.4
Fair Value, Inputs, Level 1, 2 and 3 | Corporate debt securities
Assets
Debt securities, trading	564.6	37.7
Fair Value, Inputs, Level 1, 2 and 3 | U.S. government and government agency
Assets
Debt securities, trading	1,140.9	53.2
Fair Value, Inputs, Level 1, 2 and 3 | Non-U.S. government and government agency
Assets
Debt securities, trading	121.3
Fair Value, Inputs, Level 1, 2 and 3 | U.S. states, municipalities and political subdivision
Assets
Debt securities, trading	0.9
Fair Value, Inputs, Level 1, 2 and 3 | Preferred stocks
Assets
Debt securities, trading	2.8
Fair Value, Inputs, Level 1, 2 and 3 | Fixed income mutual funds
Assets
Total equity securities	1.8
Fair Value, Inputs, Level 1, 2 and 3 | Common stocks
Assets
Total equity securities	4.1
Quoted prices in active markets (Level 1)
Assets
Debt securities, trading	1,101.2	0
Total equity securities	5.9
Total other long-term investments	0	0
Derivative assets	1.6	0
Loan participation	0
Total assets	1,108.7	0
Liabilities
Total securities sold, not yet purchased	0	0
Liability-classified capital instruments	0
Contingent consideration	0
Derivative liabilities	0	0
Total liabilities	0	0
Quoted prices in active markets (Level 1) | Asset-backed securities
Assets
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | Residential mortgage-backed securities
Assets
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | Commercial mortgage-backed securities
Assets
Debt securities, trading	0
Quoted prices in active markets (Level 1) | Bank debt
Assets
Debt securities, trading		0
Quoted prices in active markets (Level 1) | Corporate debt securities
Assets
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | U.S. government and government agency
Assets
Debt securities, trading	1,076.3	0
Liabilities
Total securities sold, not yet purchased	0	0
Quoted prices in active markets (Level 1) | Non-U.S. government and government agency
Assets
Debt securities, trading	24.9
Quoted prices in active markets (Level 1) | U.S. states, municipalities and political subdivision
Assets
Debt securities, trading	0
Quoted prices in active markets (Level 1) | Preferred stocks
Assets
Debt securities, trading	0
Quoted prices in active markets (Level 1) | Fixed income mutual funds
Assets
Total equity securities	1.8
Quoted prices in active markets (Level 1) | Common stocks
Assets
Total equity securities	4.1
Significant other observable inputs (Level 2)
Assets
Debt securities, trading	1,836.3	101.3
Total equity securities	0
Total other long-term investments	0	0
Derivative assets	0	0
Loan participation	0
Total assets	1,836.3	101.3
Liabilities
Total securities sold, not yet purchased	9.2	12
Liability-classified capital instruments	0
Contingent consideration	0
Derivative liabilities	0	0
Total liabilities	9.2	12
Significant other observable inputs (Level 2) | Asset-backed securities
Assets
Debt securities, trading	594.6	1.3
Significant other observable inputs (Level 2) | Residential mortgage-backed securities
Assets
Debt securities, trading	392.2	8.7
Significant other observable inputs (Level 2) | Commercial mortgage-backed securities
Assets
Debt securities, trading	123
Significant other observable inputs (Level 2) | Bank debt
Assets
Debt securities, trading		0.4
Significant other observable inputs (Level 2) | Corporate debt securities
Assets
Debt securities, trading	564.6	37.7
Significant other observable inputs (Level 2) | U.S. government and government agency
Assets
Debt securities, trading	64.6	53.2
Liabilities
Total securities sold, not yet purchased	9.2	12
Significant other observable inputs (Level 2) | Non-U.S. government and government agency
Assets
Debt securities, trading	96.4
Significant other observable inputs (Level 2) | U.S. states, municipalities and political subdivision
Assets
Debt securities, trading	0.9
Significant other observable inputs (Level 2) | Preferred stocks
Assets
Debt securities, trading	0
Significant other observable inputs (Level 2) | Fixed income mutual funds
Assets
Total equity securities	0
Significant other observable inputs (Level 2) | Common stocks
Assets
Total equity securities	0
Significant unobservable inputs (Level 3)
Assets
Debt securities, trading	2.8	0
Total equity securities	0
Total other long-term investments	311.2	4
Derivative assets	3.2	1.2
Loan participation	32.8
Total assets	350	5.2
Liabilities
Total securities sold, not yet purchased	0	0
Liability-classified capital instruments	135
Contingent consideration	1.5
Derivative liabilities	3.5	1
Total liabilities	140	1
Significant unobservable inputs (Level 3) | Asset-backed securities
Assets
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Residential mortgage-backed securities
Assets
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Commercial mortgage-backed securities
Assets
Debt securities, trading	0
Significant unobservable inputs (Level 3) | Bank debt
Assets
Debt securities, trading		0
Significant unobservable inputs (Level 3) | Corporate debt securities
Assets
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | U.S. government and government agency
Assets
Debt securities, trading	0	0
Liabilities
Total securities sold, not yet purchased	0	0
Significant unobservable inputs (Level 3) | Non-U.S. government and government agency
Assets
Debt securities, trading	0
Significant unobservable inputs (Level 3) | U.S. states, municipalities and political subdivision
Assets
Debt securities, trading	0
Significant unobservable inputs (Level 3) | Preferred stocks
Assets
Debt securities, trading	2.8
Significant unobservable inputs (Level 3) | Fixed income mutual funds
Assets
Total equity securities	0
Significant unobservable inputs (Level 3) | Common stocks
Assets
Total equity securities	0
Valued at NAV
Assets
Investments in funds valued at NAV	$ 1,370.7	$ 1,055.6

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Reclassification of assets, Level 2 to Level 3	$ 0	$ 0
Reclassification of liabilities, Level 2 to Level 3	0	0
Reclassification of assets, Level 3 to Level 2	0	0
Reclassification of liabilities, Level 3 to Level 2	$ 0	$ 0

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of investments measured at fair value using Level 3 inputs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 5.2	$ 4
Transfers in to (out of) Level 3	0	0
Purchases	13.6	4.4
Assets Acquired	294.9	0
Sales	(1)	0
Realized and Unrealized Gains (Losses)	37.3	0
Ending balance	350	8.4
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(1)	0
Transfers in to (out of) Level 3	0	0
Purchases	(135)	0
Assets Acquired	(2.7)	0
Sales	0	0
Realized and Unrealized Gains (Losses)	(1.3)	0
Ending balance	(140)	0
Liability-classified capital instruments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0
Transfers in to (out of) Level 3	0
Purchases	(135)
Assets Acquired	0
Sales	0
Realized and Unrealized Gains (Losses)	0
Ending balance	(135)
Contingent consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0
Transfers in to (out of) Level 3	0
Purchases	0
Assets Acquired	(0.7)
Sales	0
Realized and Unrealized Gains (Losses)	(0.8)
Ending balance	(1.5)
Derivative liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(1)	0
Transfers in to (out of) Level 3	0	0
Purchases	0	0
Assets Acquired	(2)	0
Sales	0	0
Realized and Unrealized Gains (Losses)	(0.5)	0
Ending balance	(3.5)	0
Preferred stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0
Transfers in to (out of) Level 3	0
Purchases	0
Assets Acquired	2.8
Sales	0
Realized and Unrealized Gains (Losses)	0
Ending balance	2.8
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		0
Transfers in to (out of) Level 3		0
Purchases		4.4
Assets Acquired		0
Sales		0
Realized and Unrealized Gains (Losses)		0
Ending balance		4.4
Other long-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4	4
Transfers in to (out of) Level 3	0	0
Purchases	13.6	0
Assets Acquired	259	0
Sales	(1)	0
Realized and Unrealized Gains (Losses)	35.6	0
Ending balance	311.2	$ 4
Derivative assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1.2
Transfers in to (out of) Level 3	0
Purchases	0
Assets Acquired	0.3
Sales	0
Realized and Unrealized Gains (Losses)	1.7
Ending balance	3.2
Loan participation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0
Transfers in to (out of) Level 3	0
Purchases	0
Assets Acquired	32.8
Sales	0
Realized and Unrealized Gains (Losses)	0
Ending balance	$ 32.8

Fair Value Measurements - Signi

Fair Value Measurements - Significant unobservable inputs used for recurring fair value measurements (Details) $ in Millions	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 473.1	$ 4
Debt securities, trading	2,940.3	101.3
Derivative liability, Fair value	(3.5)	(1)
Contingent consideration, Fair value	(1.5)
Liability-classified capital instruments	(135)	0
Private equity funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	119.6
Preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities, trading	2.8
Significant unobservable inputs (Level 3)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	311.2	4
Loan participation, Fair value	32.8
Debt securities, trading	2.8	0
Derivative assets, Fair value	3.2	1.2
Derivative liability, Fair value	(3.5)	$ (1)
Contingent consideration, Fair value	(1.5)
Liability-classified capital instruments	(135)
Significant unobservable inputs (Level 3) | Preferred stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities, trading	2.8
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Share price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan participation, Fair value	$ 32.8
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Share price of recent transaction | Comparable yields | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan participation, Unobservable input	0.0491
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Share price of recent transaction | Comparable yields | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan participation, Unobservable input	0.0782
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Share price of recent transaction | Comparable yields | Median
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loan participation, Unobservable input	0.0592
Significant unobservable inputs (Level 3) | Fair Value, Recurring | External valuation model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, Fair value	$ (1.5)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | External valuation model | Discounted future payments
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration, Unobservable input	(1,500,000)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Subject company transaction approach
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 152
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Subject company transaction approach | Share price | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	19.84
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Subject company transaction approach | Share price | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	23.34
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Share price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 39.6
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Share price of recent transaction | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	50.79
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 0.3
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	300,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Multiple of GAAP book value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 15
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Multiple of GAAP book value | Book value multiple | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.73
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Multiple of GAAP book value | Book value multiple | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.91
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity securities | Multiple of GAAP book value | Book value multiple | Median
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.82
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity funds | Net asset value discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 80.2
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity funds | Net asset value discount | Discount yield | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.50
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private equity funds | Net asset value discount | Discount yield | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.95
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred stock | Share price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities, trading	$ 2.8
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred stock | Share price of recent transaction | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt securities, Unobservable input	2,800,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred Stock One | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 3
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred Stock One | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	3,000,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred Stock Two | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 1.1
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Preferred Stock Two | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	1,100,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Common Stock | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 10
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Common Stock | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	10,000,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private debt instrument | Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 6.5
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private debt instrument | Discounted cash flow | Discount yield | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.0655
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private debt instrument | Discounted cash flow | Discount yield | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.0703
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private debt instrument | Discounted cash flow | Discount yield | Median
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	0.0673
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Promissory note | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 2.5
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Promissory note | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	2,500,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Membership Interest | Purchase price of recent transaction
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Total other long-term investments	$ 1
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Membership Interest | Purchase price of recent transaction | Purchase price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other long-term investments, Unobservable input	1,000,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Equity warrants | Pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative assets, Fair value	$ 0.3
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Equity warrants | Pricing model | Strike price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative asset, Unobservable input	200,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Weather derivatives | Third party appraisal
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, Fair value	$ (0.3)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Weather derivatives | Third party appraisal | Broker quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Liability, Measurement Input	(300,000)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Currency swaps | Third party appraisal
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability, Fair value	$ (2.2)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Currency swaps | Third party appraisal | Broker quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative Liability, Measurement Input	(2,200,000)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Upside rights | External valuation model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments	$ (6.5)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Upside rights | External valuation model | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments measurement input	6,500,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private warrants | Pricing model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments	$ (7.3)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Private warrants | Pricing model | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments measurement input	1.81
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Contingent value rights | External valuation model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments	$ (27)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Contingent value rights | External valuation model | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments measurement input	5.91
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Series A preference shares | External valuation model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments	$ (40.8)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Series A preference shares | External valuation model | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments measurement input	40,800,000
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Merger warrants | External valuation model
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments	$ (53.4)
Significant unobservable inputs (Level 3) | Fair Value, Recurring | Merger warrants | External valuation model | Share price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Liability-classified capital instruments measurement input	2.54

Fair Value Measurements - Finan

Fair Value Measurements - Financial instruments not measured at fair value (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Level 3 | Subordinated Notes | Estimate of Fair Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	$ 307.2
Level 3 | Subordinated Notes | Reported Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	307.9
Level 3 | Senior Notes | 2016 SIG Senior Notes | Estimate of Fair Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	405
Level 3 | Senior Notes | 2016 SIG Senior Notes | Reported Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	406.8
Level 2 | Senior Notes | 2015 TPRUSA Senior Notes | Estimate of Fair Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	117.5	$ 117.8
Level 2 | Senior Notes | 2015 TPRUSA Senior Notes | Reported Value Measurement
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	$ 114.3	$ 114.3

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) - Interest rate cap $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)financial_institution
Derivative
Number of financial institutions | financial_institution	2
Collateral held | $	$ 0.1

Derivatives - Classification an

Derivatives - Classification and fair value of derivatives (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative
Derivative liabilities at fair value	$ 3.5	$ 1
Derivatives not designated as hedging instruments | Interest rate cap
Derivative
Notional Value	250
Derivatives not designated as hedging instruments | Interest rate cap | Other assets
Derivative
Derivative assets at fair value	0
Derivatives not designated as hedging instruments | Interest rate cap | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	0
Derivatives not designated as hedging instruments | Foreign currency swaps
Derivative
Notional Value	40
Derivatives not designated as hedging instruments | Foreign currency swaps | Other assets
Derivative
Derivative assets at fair value	0
Derivatives not designated as hedging instruments | Foreign currency swaps | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	2.3
Derivatives not designated as hedging instruments | Weather derivatives
Derivative
Notional Value	31.2
Derivatives not designated as hedging instruments | Weather derivatives | Other assets
Derivative
Derivative assets at fair value	0
Derivatives not designated as hedging instruments | Weather derivatives | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	0.2
Derivatives not designated as hedging instruments | Foreign currency futures contracts
Derivative
Notional Value	100.8
Derivatives not designated as hedging instruments | Foreign currency futures contracts | Other assets
Derivative
Derivative assets at fair value	0
Derivatives not designated as hedging instruments | Foreign currency futures contracts | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	0
Derivatives not designated as hedging instruments | Foreign currency call options
Derivative
Notional Value	50.6
Derivatives not designated as hedging instruments | Foreign currency call options | Other assets
Derivative
Derivative assets at fair value	1.6
Derivatives not designated as hedging instruments | Foreign currency call options | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	0
Derivatives not designated as hedging instruments | Equity warrants
Derivative
Notional Value	0.3
Derivatives not designated as hedging instruments | Equity warrants | Other assets
Derivative
Derivative assets at fair value	0.3
Derivatives not designated as hedging instruments | Equity warrants | Accounts payable, accrued expenses and other liabilities
Derivative
Derivative liabilities at fair value	$ 0

Derivatives - Classification _2

Derivatives - Classification and net impact on earnings of derivatives (Details) - Derivatives not designated as hedging instruments $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Foreign currency swaps | Foreign exchange gains
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	$ (0.4)
Weather derivatives | Net corporate and other expenses
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	(0.1)
Foreign currency futures contracts | Foreign exchange gains
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	(3.7)
Foreign currency call options | Foreign exchange gains
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	$ (1.6)

Derivatives - Listing currency,

Derivatives - Listing currency, fair value and notional amounts of underwriting-related derivatives (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative
Derivative liabilities, Fair value	$ 3.5	$ 1
Reinsurance contracts accounted for as derivatives | GBP
Derivative
Derivative assets, Fair value	2.9	1.2
Derivative Assets, Notional Amounts	2.9	4.2
Derivative liabilities, Fair value	1	1
Derivative Liabilities, Notional Amounts	13.4	15.7
Underwriting-related derivatives
Derivative
Derivative assets, Fair value	2.9	1.2
Derivative Assets, Notional Amounts	2.9	4.2
Derivative liabilities, Fair value	1	1
Derivative Liabilities, Notional Amounts	$ 13.4	$ 15.7

Loss and loss adjustment expe_3

Loss and loss adjustment expense reserves - Activity in the loss and loss adjustment expense reserves (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for loss and loss adjustment expenses, beginning of period	$ 1,310.1	$ 1,111.7
Less: loss and loss adjustment expenses recoverable, beginning of period	(14.4)	(5.5)
Less: deferred charges on retroactive reinsurance contracts	(6)	(6.7)
Net reserves for loss and loss adjustment expenses, beginning of period	1,289.7	1,099.5
Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in:
Current year	147.7	92.2
Prior years	0.4	(4.4)
Total incurred loss and loss adjustment expenses	148.1	87.8
Net loss and loss adjustment expenses paid in respect of losses occurring in:
Current year	(15.9)	(10.1)
Prior years	(117.2)	(74)
Total net paid losses	(133.1)	(84.1)
Foreign currency translation	(10.6)	(10.2)
Amounts acquired as a result of Sirius Group acquisition	2,467.8	0
Net reserves for loss and loss adjustment expenses, end of period	3,761.9	1,093
Plus: loss and loss adjustment expenses recoverable, end of period	492.6	6.9
Plus: deferred charges on retroactive reinsurance contracts	4.8	8
Gross reserves for loss and loss adjustment expenses, end of period	$ 4,259.3	$ 1,107.9

Loss and loss adjustment expe_4

Loss and loss adjustment expense reserves - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Insurance [Abstract]
Increase (decrease) in prior years' reserves	$ 0.4	$ (4.4)
Unfavorable (favorable) reserve development related to an increase (decrease) in loss reserve estimates		11
Increase (decrease) in loss reserves resulting from increases (decreases) in premium earnings estimates		6.6
Improvement in net underwriting results		$ 3.2

Third party reinsurance (Detail

Third party reinsurance (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Insurance [Abstract]
Premiums ceded	$ 56.3	$ 2.5
Loss and loss adjustment expenses recoverable	$ 492.6	$ 6.9	$ 14.4	$ 5.5

Allowance for expected credit_3

Allowance for expected credit losses - Summary of allowance for expected credit losses (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Insurance and reinsurance balances receivable, net	$ 1,613.8	$ 441.9
Loss and loss adjustment expenses recoverable, net	492.6	14.4	$ 6.9	$ 5.5
Other assets	15.9	0
Total assets in scope	$ 2,122.3	$ 456.3

Allowance for expected credit_4

Allowance for expected credit losses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for expected credit losses	$ 18		$ 0.6
Current expected credit losses	$ 17.4	$ 0.2
Assets within scope of credit losses | Credit concentration risk | AM Best or S&P
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	66.00%
Assets within scope of credit losses | Credit concentration risk | AM Best or S&P | AM Best or S&P, rated A- or better
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	78.00%
Sirius Group
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current expected credit losses	$ 16.8

Deposit contracts (Details)

Deposit contracts (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Deposit Contracts, Liabilities [Roll Forward]
Balance, beginning of period	$ 153	$ 172.3
Consideration received	0.4	0.5
Net investment expense allocation	0.8	0.9
Payments	(3.4)	(20.8)
Foreign currency translation	(0.1)	$ 0.1
Balance, end of period	$ 150.7

Debt and letter of credit fac_3

Debt and letter of credit facilities - Summary of debt obligations (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total debt	$ 829	$ 114.3
Subordinated Notes
Debt Instrument [Line Items]
Debt, at face value	315.1
Unamortized discount	(7.2)
Total debt	$ 307.9
Effective rate	4.10%
Senior Notes | 2016 SIG Senior Notes
Debt Instrument [Line Items]
Debt, at face value	$ 400
Unamortized premium	6.8
Total debt	$ 406.8
Effective rate	4.50%
Senior Notes | 2015 TPRUSA Senior Notes
Debt Instrument [Line Items]
Debt, at face value	$ 115	115
Unamortized issuance costs	(0.7)	(0.7)
Total debt	$ 114.3	$ 114.3
Effective rate	7.00%	7.00%

Debt and letter of credit fac_4

Debt and letter of credit facilities - Summary of letter of credit facilities (Details) - Standby letters of credit	Mar. 31, 2021USD ($)
Line of Credit Facility
Issued	$ 1,385,600,000
Cash and Cash Equivalents
Line of Credit Facility
Collateral	463,600,000
Debt securities
Line of Credit Facility
Collateral	751,800,000
Committed - Secured letters of credit facilities
Line of Credit Facility
Committed Capacity	2,026,000,000
Issued	1,089,500,000
Committed - Secured letters of credit facilities | Cash and Cash Equivalents
Line of Credit Facility
Collateral	168,200,000
Committed - Secured letters of credit facilities | Debt securities
Line of Credit Facility
Collateral	751,800,000
Uncommitted - Secured letters of credit facilities
Line of Credit Facility
Issued	296,100,000
Uncommitted - Secured letters of credit facilities | Cash and Cash Equivalents
Line of Credit Facility
Collateral	295,400,000
Uncommitted - Secured letters of credit facilities | Debt securities
Line of Credit Facility
Collateral	$ 0

Debt and letter of credit fac_5

Debt and letter of credit facilities - Narrative (Details)	Feb. 26, 2021USD ($)	Sep. 22, 2017USD ($)	Nov. 01, 2016USD ($)	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)	Sep. 22, 2017SEK (kr)
Debt Instrument [Line Items]
Interest expense				$ 4,900,000	$ 2,000,000
Foreign exchange gains				12,400,000	8,200,000
Revolving Credit Facility
Debt Instrument [Line Items]
Contractual term	3 years
Maximum borrowing capacity	$ 300,000,000
Extension term	12 months
Outstanding borrowings				0
Subordinated Notes
Debt Instrument [Line Items]
Face value of debt issued		$ 346,100,000				kr 2,750,000,000
Debt issue price, percentage		100.00%
Interest expense				1,200,000
Foreign exchange gains				13,400,000
Senior Notes | 2016 SIG Senior Notes
Debt Instrument [Line Items]
Face value of debt issued			$ 400,000,000
Debt issue price, percentage			99.20%
Interest expense				1,700,000
Proceeds from issuance of debt, net of costs			$ 392,400,000
Interest rate			4.60%
Senior Notes | 2015 TPRUSA Senior Notes
Debt Instrument [Line Items]
Face value of debt issued				115,000,000
Interest expense				$ 2,000,000	$ 2,000,000
Interest rate				7.00%

Net investment income (loss) -

Net investment income (loss) - Summary of net investment income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Investment Income [Line Items]
Other investment expenses	$ (1)	$ (0.2)
Net investment income (loss)	186.5	(185)
Debt securities
Net Investment Income [Line Items]
Investment income (loss)	(7.8)	19.7
Equity securities
Net Investment Income [Line Items]
Investment income (loss)	0.3	0
Other long-term investments
Net Investment Income [Line Items]
Investment income (loss)	49.2	0
Related party investment funds
Net Investment Income [Line Items]
Investment income (loss)	153.2	(200.8)
Before other investment expenses and investment loss on cash and cash equivalents
Net Investment Income [Line Items]
Investment income (loss)	194.9	(181.1)
Cash and cash equivalents
Net Investment Income [Line Items]
Investment income (loss)	$ (7.4)	$ (3.7)

Net investment income (loss) _2

Net investment income (loss) - Summary of net realized and unrealized gains on investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 19.3	$ 2.7
Gross realized losses	(0.4)	(1.7)
Net realized gains on investments	18.9	1
Net change in unrealized gain (loss) on securities, derivative contracts and foreign currency translations	12.6	10.6
Net realized and unrealized gains on investments	31.5	11.6
Realized gains (losses) due to foreign currency	2.1	(0.1)
Unrealized losses due to foreign currency	$ (16.3)	$ (8.6)

Net investment income (loss) _3

Net investment income (loss) - Summary of net realized investment gains (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt securities	$ 6.3	$ (0.7)
Equity securities	0.4	0
Other long-term investments	9.9	0
Net investment income on cash and cash equivalents	2.3	1.7
Net realized gains on investments	$ 18.9	$ 1

Net investment income (loss) _4

Net investment income (loss) - Summary of net unrealized investment gains (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt securities	$ (16.9)	$ 19.4
Equity securities	(0.1)	0
Other long-term investments	39.3	0
Net investment loss on cash and cash equivalents	(9.7)	(8.8)
Net unrealized investment gains	$ 12.6	$ 10.6

Net investment income (loss) _5

Net investment income (loss) - Summary of gains attributable to unrealized investment gains on level 3 investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net Investment Income [Line Items]
Other long-term investments	$ 39.3	$ 0
Net unrealized investment gains	12.6	10.6
Level 3
Net Investment Income [Line Items]
Other long-term investments	35.6	0
Net unrealized investment gains	$ 35.6	$ 0

Income taxes (Details)

Income taxes (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Feb. 25, 2021subsidiary
Segment Reporting Information [Line Items]
Number of operating subsidiaries | subsidiary				1
Income tax expense	$ 9,800,000	$ 400,000
Pre-tax income (loss)	$ 142,200,000	$ (183,200,000)
Effective tax rate	6.90%
Provision for taxes related to BEAT or GILTI	$ 0		$ 0
Net deferred tax asset	33,500,000
Unrecognized Tax Benefits	3,100,000
Unrecognized tax benefits that would impact the effective tax rate	2,500,000
Unrecognized tax benefits that would not impact the effective tax rate	600,000
U.S.
Segment Reporting Information [Line Items]
Net deferred tax asset	71,400,000
Luxembourg
Segment Reporting Information [Line Items]
Net deferred tax asset	147,000,000
UK
Segment Reporting Information [Line Items]
Net deferred tax liabilities	(6,100,000)
Sweden
Segment Reporting Information [Line Items]
Net deferred tax liabilities	(170,900,000)
Other
Segment Reporting Information [Line Items]
Net deferred tax liabilities	$ (7,900,000)

Shareholders' equity - Common s

Shareholders' equity - Common shares issued and outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Movement In Common Stock Outstanding [Roll Forward]
Common shares issued, beginning of period	95,582,733	94,225,498
Issuance of common shares for Sirius Group acquisition	58,331,196	0
Issuance of common shares to related party	6,093,842	0
Common shares issued, end of period	161,891,354	94,881,229
Restricted shares with service condition
Movement In Common Stock Outstanding [Roll Forward]
Shares granted, net of forfeitures and shares withheld	2,081,001	283,008
Restricted shares with service and performance condition
Movement In Common Stock Outstanding [Roll Forward]
Shares granted, net of forfeitures and shares withheld	(197,418)	372,723

Shareholders' equity - Narrativ

Shareholders' equity - Narrative (Details)	Feb. 26, 2021directorperiod$ / sharesshares	Mar. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020$ / sharesshares
Class of Stock [Line Items]
Common shares authorized (in shares)		300,000,000
Common shares, par value (in dollars per share) | $ / shares		$ 0.10
Preference shares
Class of Stock [Line Items]
Preference shares, shares authorized (in shares)		30,000,000
Preference shares, par value (in dollars per share) | $ / shares		$ 0.10
Series B preference shares
Class of Stock [Line Items]
Preference shares, shares authorized (in shares)		8,000,000	8,000,000
Preference shares, par value (in dollars per share) | $ / shares	$ 0.10	$ 0.10	$ 0.10
Shares issued (in shares)	8,000,000
Dividend rate	8.00%
Voting rights triggering event, number of dividend periods not paid | period	6
Voting rights triggered, number of directors eligible to elect | director	2
Dividend rate reset period	5 years
Each five-year anniversary triggering event, redemption percentage	100.00%
Rating agency triggering event, redemption percentage	102.00%
Capital disqualification triggering event, redemption percentage	100.00%
Tax triggering event, redemption percentage	100.00%
Dividends paid to preference shareholders | $		$ 0
Series B preference shares | 5-year U.S. treasury rate
Class of Stock [Line Items]
Dividend rate basis spread on variable rate	7.298%

Share-based compensation - Shar

Share-based compensation - Share-based compensation expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 2.3	$ 1.6
Restricted shares with service condition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2	0.5
Restricted shares with service and performance condition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 0.3	$ 1.1

Share-based compensation - Narr

Share-based compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Unamortized share compensation expense	$ 37.9	$ 14.2
Unamortized share compensation expense, period of recognition	2 years	1 year 10 months 24 days

Share-based compensation - Opti

Share-based compensation - Options activity (Details)	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Number of options
Beginning of period (in shares) | shares	8,255,810
Granted (in shares) | shares	2,183,853
End of period (in shares) | shares	10,439,663
Weighted average exercise price
Beginning of period (in dollars per share) | $ / shares	$ 13.45
Granted (in dollars per share) | $ / shares	10.78
End of period (in dollars per share) | $ / shares	$ 12.89

Share-based compensation - Info

Share-based compensation - Information about options outstanding and exercisable (Details)	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares) | shares	10,439,663
Options outstanding, weighted average exercise price (in dollars per share)	$ 12.89
Options outstanding, remaining contractual life	1 year 1 month 6 days
Options exercisable (in shares) | shares	10,039,663
Options exercisable, weighted average exercise price (in dollars per share)	$ 11.06
$9.83 - $10.89
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	9.83
Upper range limit (in dollars per share)	$ 10.89
Options outstanding (in shares) | shares	6,528,039
Options outstanding, weighted average exercise price (in dollars per share)	$ 9.98
Options outstanding, remaining contractual life	7 months 6 days
Options exercisable (in shares) | shares	6,528,039
Options exercisable, weighted average exercise price (in dollars per share)	$ 9.98
$15.00 - $16.89
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	15
Upper range limit (in dollars per share)	$ 16.89
Options outstanding (in shares) | shares	2,190,696
Options outstanding, weighted average exercise price (in dollars per share)	$ 15.75
Options outstanding, remaining contractual life	2 years 8 months 12 days
Options exercisable (in shares) | shares	1,790,696
Options exercisable, weighted average exercise price (in dollars per share)	$ 15.92
$20.00 - $25.05
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	20
Upper range limit (in dollars per share)	$ 25.05
Options outstanding (in shares) | shares	1,720,928
Options outstanding, weighted average exercise price (in dollars per share)	$ 20.28
Options outstanding, remaining contractual life	1 year
Options exercisable (in shares) | shares	1,720,928
Options exercisable, weighted average exercise price (in dollars per share)	$ 20.28

Share-based compensation - Rest

Share-based compensation - Restricted share award and RSU activity with service condition (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Restricted shares with service condition
Number of non- vested restricted shares
Beginning of period (in shares)	1,171,058	340,767
Granted (in shares)	1,188,380	1,029,373
Forfeited (in shares)		(16,434)
Vested (in shares)	(204,864)	(182,648)
End of period (in shares)	2,154,574	1,171,058
Weighted average grant date fair value
Beginning of period (in dollars per share)	$ 8.80	$ 11.83
Granted (in dollars per share)	10.21	8.30
Forfeited (in dollars per share)		9.77
Vested (in dollars per share)	9.89	10.10
End of period (in dollars per share)	$ 9.47	$ 8.80
RSUs
Number of non- vested restricted shares
Beginning of period (in shares)	0
Granted (in shares)	4,935,144
Vested (in shares)	(2,051,730)
End of period (in shares)	2,883,414	0
Weighted average grant date fair value
Beginning of period (in dollars per share)	$ 0
Granted (in dollars per share)	10.21
Vested (in dollars per share)	10.21
End of period (in dollars per share)	$ 10.21	$ 0

Share-based compensation - Re_2

Share-based compensation - Restricted share award activity with service and performance condition (Details) - Restricted shares with service and performance condition - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Number of non- vested restricted shares
Beginning of period (in shares)	1,762,935	1,890,529
Granted (in shares)		749,322
Forfeited (in shares)	(166,702)	(372,476)
Vested (in shares)	(300,469)	(504,440)
End of period (in shares)	1,295,764	1,762,935
Number of non- vested restricted shares probable of vesting
Beginning of period (in shares)	1,402,580	1,314,036
Granted (in shares)		499,542
Forfeited (in shares)	0	(39,214)
Vested (in shares)	(300,469)	(504,440)
Change in estimated restricted shares considered probable of vesting (in shares)	(238,279)	132,656
End of period (in shares)	863,832	1,402,580
Weighted average grant date fair value
Beginning of period (in dollars per share)	$ 10.98	$ 12.43
Granted (in dollars per share)		9.46
Forfeited (in dollars per share)	14.03	12.12
Vested (in dollars per share)	14.03	12.16
Change in estimated restricted shares considered probable of vesting (in dollars per share)	10.33	11.28
End of period (in dollars per share)	$ 10.11	$ 10.98

Variable interest entities - Na

Variable interest entities - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Total assets	$ 10,169.7	$ 3,535.2
Total liabilities	$ 7,560.4	1,969.9
Common shares, par value (in dollars per share)	$ 0.10
Alstead Re
Variable Interest Entity [Line Items]
Total assets	$ 7.3
Total liabilities	2.9
Arcadian
Variable Interest Entity [Line Items]
Total assets	3.5	3.3
Total liabilities	$ 0.5	$ 0.6
Ownership percentage	49.00%
Common share ownership (in shares)	980,000
Common shares, par value (in dollars per share)	$ 1
Maximum financial exposure	$ 18
Variable interest entity, primary beneficiary | TP Enhanced Fund | TP GP
Variable Interest Entity [Line Items]
Ownership percentage	10.90%
Variable interest entity, not primary Beneficiary | TP Enhanced Fund
Variable Interest Entity [Line Items]
Ownership percentage	89.10%

Variable interest entities - Re

Variable interest entities - Reconciliation of noncontrolling interests (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance, beginning of period	$ 1.4
Impact of Sirius acquisition	0.3
Net income attributable to noncontrolling interests	0	$ 0
Contributions	0.1
Balance, end of period	$ 1.8

Variable interest entities - To

Variable interest entities - Total assets and maximum exposure to loss for unconsolidated variable interest entities (Details) $ in Millions	Mar. 31, 2021USD ($)
Maximum Exposure to Loss
On-Balance Sheet	$ 213.7
Off-Balance Sheet	5.1
Total	218.8
Other long-term investments
Maximum Exposure to Loss
On-Balance Sheet	213.7
Off-Balance Sheet	5.1
Total	218.8
Variable interest entity, not primary Beneficiary
Total VIE Assets
Total VIE Assets	250.3
Variable interest entity, not primary Beneficiary | Other long-term investments
Total VIE Assets
Total VIE Assets	$ 250.3

Variable interest entities - TP

Variable interest entities - TP Enhanced Fund summarized financial information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Investment income (loss)
Net realized gain from securities, derivative contracts and foreign currency translations	$ 18,900,000	$ 1,000,000
Net change in unrealized gain (loss) on securities, derivative contracts and foreign currency translations	12,600,000	10,600,000
Net income (loss) from currencies	12,400,000	8,200,000
Other income	1,800,000	4,200,000
Total revenues	451,100,000	(38,700,000)
Operating Expenses [Abstract]
Interest expense	4,900,000	2,000,000
Net corporate and other expenses	68,300,000	6,400,000
Net income (loss)	132,400,000	(183,600,000)
Assets
Total investments in securities and affiliated funds	4,628,100,000		$ 1,160,900,000
Cash and cash equivalents	932,400,000		526,000,000
Due from brokers	37,800,000		94,900,000
Interest and dividends receivable	10,300,000		900,000
Other assets	146,200,000		18,800,000
Total assets	10,169,700,000		3,535,200,000
Liabilities
Due to brokers	26,200,000		0
Accounts payable and accrued expenses	154,400,000		17,600,000
Securities sold, not yet purchased, at fair value	9,200,000		12,000,000
Derivative liabilities at fair value	3,500,000		1,000,000
Withdrawals payable to General Partner	0
Total liabilities	7,560,400,000		1,969,900,000
TP Enhanced Fund
Investment income (loss)
Net realized gain from securities, derivative contracts and foreign currency translations	148,400,000	15,600,000
Net change in unrealized gain (loss) on securities, derivative contracts and foreign currency translations	71,500,000	(251,500,000)
Net income (loss) from currencies	800,000	(300,000)
Dividend and interest income	5,400,000	4,400,000
Other income	0	700,000
Total revenues	226,100,000	(231,100,000)
Operating Expenses [Abstract]
Management Fee Expense	4,000,000	3,900,000
Interest expense	1,500,000	2,700,000
Dividends Paid on Securities Sold, Not Yet Purchased	1,500,000	1,300,000
Administrative and professional fees	700,000	400,000
Net corporate and other expenses	1,300,000	500,000
Total expenses	9,000,000	8,800,000
Net income (loss)	217,100,000	$ (239,900,000)
Assets
Total investments in securities and affiliated funds	2,409,100,000		2,200,900,000
Cash and cash equivalents	40,600,000		40,100,000
Due from brokers	144,700,000		124,600,000
Derivative assets	53,300,000		37,000,000
Interest and dividends receivable	3,000,000		3,200,000
Other assets	2,900,000		3,900,000
Total assets	2,653,600,000		2,409,700,000
Liabilities
Due to brokers	898,300,000		894,000,000
Accounts payable and accrued expenses	1,300,000		1,000,000
Securities sold, not yet purchased, at fair value	351,200,000		183,000,000
Securities sold under agreement to repurchase	2,500,000		5,500,000
Derivative liabilities at fair value	13,700,000		23,700,000
Withdrawals payable to General Partner	0		75,000,000
Management fee payable	0		200,000
Interest and dividends payable	1,000,000		700,000
Total liabilities	1,268,000,000		1,183,100,000
Total partners' capital	$ 1,385,600,000		$ 1,226,600,000

Investments in unconsolidated_3

Investments in unconsolidated entities - Components of other long-term investments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	$ 473.1	$ 4
Equity method eligible unconsolidated entities, at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	218	0
Other unconsolidated investments, at fair value
Debt and Equity Securities, FV-NI [Line Items]
Total other long-term investments	$ 255.1	$ 4

Investments in unconsolidated_4

Investments in unconsolidated entities - Ownership interests in equity method eligible unconsolidated entities (Details)	Mar. 31, 2021
BE Reinsurance Limited
Schedule of Equity Method Investments [Line Items]
Ownership interest	24.90%
BioVentures Investors (Offshore) IV LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	73.00%
Camden Partners Strategic Fund V (Cayman), LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	39.40%
Diamond LS I LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	15.40%
Gateway Fund LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	22.90%
Monarch
Schedule of Equity Method Investments [Line Items]
Ownership interest	12.80%
New Energy Capital Infrastructure Credit Fund LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	29.80%
New Energy Capital Infrastructure Offshore Credit Fund LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	29.80%
Pie Preferred Stock
Schedule of Equity Method Investments [Line Items]
Ownership interest	9.60%
Pie Series B Preferred Stock
Schedule of Equity Method Investments [Line Items]
Ownership interest	6.90%
Pie Series C Preferred Stock
Schedule of Equity Method Investments [Line Items]
Ownership interest	0.50%
Quintana Energy Partners
Schedule of Equity Method Investments [Line Items]
Ownership interest	21.80%
Tuckerman Capital V LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	48.30%
Tuckerman Capital V Co-Investment I LP
Schedule of Equity Method Investments [Line Items]
Ownership interest	49.00%

Earnings (loss) per share ava_3

Earnings (loss) per share available to SiriusPoint common shareholders - Computation of basic and diluted earnings (loss) per share available to SiriusPoint common shareholders (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Weighted-average number of common shares outstanding:
Basic number of common shares outstanding (in shares)	116,760,760	92,191,837
Dilutive effect of warrants (in shares)	51,650	0
Diluted number of common shares outstanding (in shares)	118,146,341	92,191,837
Basic earnings (loss) per common share:
Net income allocated to SiriusPoint participating common shareholders	$ 130.9	$ (183.6)
Net income allocated to SiriusPoint participating common shareholders	(6.5)	0
Net income (loss) available to SiriusPoint common shareholders	$ 124.4	$ (183.6)
Basic earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ 1.07	$ (1.99)
Diluted earnings (loss) per common share:
Net income allocated to SiriusPoint participating common shareholders	$ 130.9	$ (183.6)
Net income allocated to SiriusPoint participating common shareholders	(6.5)	0
Net income (loss) allocated to SiriusPoint common shareholders	$ 124.4	$ (183.6)
Diluted earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ 1.05	$ (1.99)
Options
Weighted-average number of common shares outstanding:
Dilutive effect of share-based payment awards (in shares)	184,470	0
Restricted shares with service and performance condition
Weighted-average number of common shares outstanding:
Dilutive effect of share-based payment awards (in shares)	1,149,461	0

Earnings (loss) per share ava_4

Earnings (loss) per share available to SiriusPoint common shareholders - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		5,117,702
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	4,120,926
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	25,035,220
Upside rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	10,000,000

Related party transactions - Na

Related party transactions - Narrative (Details) - USD ($)	Feb. 26, 2021	Mar. 31, 2021	Mar. 31, 2020	Mar. 01, 2021	Jan. 01, 2019
Related Party Transaction [Line Items]
Receivables from affiliates		$ 48,300,000
Payables to affiliates		0
Legal expenses		42,200,000	$ 3,900,000
Management fees
Related Party Transaction [Line Items]
Legal expenses		4,100,000	3,900,000
Performance fees
Related Party Transaction [Line Items]
Legal expenses		38,100,000	$ 0
Beneficial owner
Related Party Transaction [Line Items]
Legal expenses		0
Affiliated entity
Related Party Transaction [Line Items]
Gross written premiums		$ 20,200,000
Shares purchased (in shares)	6,093,842
Purchase price per share (in dollars per share)	$ 7.9828
Affiliated entity | Management fees | Third Point LLC - 2019 LPA
Related Party Transaction [Line Items]
Fee percentage					1.25%
Affiliated entity | Management fees | Third Point LLC
Related Party Transaction [Line Items]
Fee percentage	1.25%
Affiliated entity | Management fees | Third Point LLC, TPIPS IMA
Related Party Transaction [Line Items]
Fee percentage	0.005%
Affiliated entity | Performance fees | TP GP
Related Party Transaction [Line Items]
Fee percentage		20.00%
Affiliated entity | Performance fees | TP Venture GP
Related Party Transaction [Line Items]
Fee percentage				20.00%

Related party transactions - Su

Related party transactions - Summary of management and performance fees (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Related Party Transaction [Line Items]
Total management and performance fees to related parties	$ 42.2	$ 3.9
Management fees
Related Party Transaction [Line Items]
Total management and performance fees to related parties	4.1	3.9
Performance fees
Related Party Transaction [Line Items]
Total management and performance fees to related parties	$ 38.1	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	Sep. 16, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Class of Warrant or Right [Line Items]
Operating lease expense		$ 1,300,000	$ 200,000
Operating lease right-of-use assets		$ 19,800,000		$ 800,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		Other assets		Other assets
Operating lease liabilities		$ 25,500,000		$ 800,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]		Accounts payable, accrued expenses and other liabilities		Accounts payable, accrued expenses and other liabilities
Affiliated entity
Class of Warrant or Right [Line Items]
Maximum loan commitment	$ 18,000,000
Interest rate	8.00%
Amount drawn		$ 0
Founder and Advisor Warrants
Class of Warrant or Right [Line Items]
Number of shares in which the warrants can be converted (in shares)		3,494,979
Warrant exercise price (in dollars per share)		$ 10

Commitments and Contingencies_2

Commitments and Contingencies - Lease balances (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating lease right-of-use assets	$ 19.8	$ 0.8
Operating lease liabilities	$ 25.5	$ 0.8
Weighted average lease term (years)	3 years	1 year
Weighted average discount rate	3.40%	7.00%

Commitments and Contingencies_3

Commitments and Contingencies - Future minimum rental commitments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2021	$ 8.3
2022	9.2
2023	5.7
2024	2.4
2025 and thereafter	1.3
Total future annual minimum rental payments	26.9
Less: present value discount	(1.4)
Total lease liability	$ 25.5	$ 0.8