SiriusPoint (SPNT) 10-Q 1 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 26, 2024
Entity Listings [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
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	98-1599372
Entity Address, Address Line One	Point Building
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
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		170,482,223
Entity Central Index Key	0001576018
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Shares, $0.10 par value
Entity Listings [Line Items]
Title of 12(b) Security	Common Shares, $0.10 par value
Trading Symbol	SPNT
Security Exchange Name	NYSE
8.00% Resettable Fixed Rate Preference Shares, Series B, $0.10 par value, $25.00 liquidation preference per share
Entity Listings [Line Items]
Title of 12(b) Security	8.00% Resettable Fixed Rate Preference Shares, Series B, $0.10 par value, $25.00 liquidation preference per share
Trading Symbol	SPNT PB
Security Exchange Name	NYSE

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets
Debt securities, available for sale, at fair value, net of allowance for credit losses of $0.0 (2023 - $0.0) (cost - $5,075.4; 2023 - $4,754.6)	$ 5,057.5	$ 4,755.4
Debt securities, trading, at fair value (cost - $433.3; 2023 - $568.1)	406	534.9
Short-term investments, at fair value (cost - $330.0; 2023 - $370.8)	329.9	371.6
Investments in related party investment funds, at fair value	105.6	105.6
Other long-term investments, at fair value (cost - $343.1; 2023 - $356.2) (includes related party investments at fair value of $170.6 (2023 - $173.7))	296.6	308.5
Equity securities, trading, at fair value (cost - $1.6; 2023 - $1.9)	1.6	1.6
Total investments	6,197.2	6,077.6
Cash and cash equivalents	867.5	969.2
Restricted cash and cash equivalents	218.9	132.1
Redemption receivable from related party investment fund	0	3
Due from brokers	16.4	5.6
Interest and dividends receivable	44.5	42.3
Insurance and reinsurance balances receivable, net	2,127.2	1,966.3
Deferred acquisition costs, net	320.8	308.9
Unearned premiums ceded	494.8	449.2
Loss and loss adjustment expenses recoverable, net	2,233.8	2,295.1
Deferred tax asset	290.7	293.6
Intangible assets	149.8	152.7
Other assets	174.2	175.9
Total assets	13,135.8	12,871.5
Liabilities
Loss and loss adjustment expense reserves	5,565.3	5,608.1
Unearned premium reserves	1,715.7	1,627.3
Reinsurance balances payable	1,780.5	1,736.7
Deposit liabilities	128.8	134.4
Deferred gain on retroactive reinsurance	25.8	27.9
Debt	770.6	786.2
Due to brokers	60.7	6.2
Deferred tax liability	48.9	68.7
Liability-classified capital instruments	83.2	67.3
Accounts payable, accrued expenses and other liabilities	335.9	278.1
Total liabilities	10,515.4	10,340.9
Commitments and contingent liabilities
Shareholders’ equity
Common shares (issued and outstanding: 169,753,232; 2023 - 168,120,022)	17	16.8
Additional paid-in capital	1,711.2	1,693
Retained earnings	691.8	601
Accumulated other comprehensive income (loss), net of tax	(17.4)	3.1
Shareholders’ equity attributable to SiriusPoint shareholders	2,602.6	2,513.9
Noncontrolling interests	17.8	16.7
Total shareholders’ equity	2,620.4	2,530.6
Total liabilities, noncontrolling interests and shareholders’ equity	13,135.8	12,871.5
Series B preference shares
Shareholders’ equity
Series B preference shares (par value $0.10; authorized and issued: 8,000,000)	$ 200	$ 200

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt securities, available for sale, cost	$ 5,075.4	$ 4,754.6
Debt securities, trading, cost	433.3	568.1
Debt securities, available for sale, allowance for credit losses	0	0
Short-term investments, cost	330	370.8
Other long-term investments, cost	343.1	356.2
Related party investments at fair value	170.6	173.7
Equity securities, trading, cost	$ 1.6	$ 1.9
Common share, shares issued (in shares)	169,753,232	168,120,022
Common share, shares outstanding (in shares)	169,753,232	168,120,022
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

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Net premiums earned	$ 593.8	$ 595.5
Net investment income	78.8	61.7
Net realized and unrealized investment gains	1	11.3
Net realized and unrealized investment gains from related party investment funds	0	0.8
Net investment income and net realized and unrealized investment gains	79.8	73.8
Other revenues	11.9	8.8
Total revenues	685.5	678.1
Expenses
Loss and loss adjustment expenses incurred, net	317.5	267.1
Acquisition costs, net	144.9	119.7
Other underwriting expenses	41.8	52.2
Net corporate and other expenses	56	60
Intangible asset amortization	2.9	2.4
Interest expense	20.5	12.8
Foreign exchange (gains) losses	(3.7)	0.1
Total expenses	579.9	514.3
Income before income tax expense	105.6	163.8
Income tax expense	(9.7)	(25.5)
Net income	95.9	138.3
Net income attributable to noncontrolling interests	(1.1)	(2.4)
Net income available to SiriusPoint	94.8	135.9
Dividends on Series B preference shares	(4)	(4)
Net income available to SiriusPoint common shareholders	90.8	131.9
Net income available to SiriusPoint common shareholders	$ 90.8	$ 131.9
Earnings per share available to SiriusPoint common shareholders
Basic earnings per share available to SiriusPoint common shareholders (in dollars per share)	$ 0.50	$ 0.76
Diluted earnings per share available to SiriusPoint common shareholders (in dollars per share)	$ 0.49	$ 0.74
Weighted average number of common shares used in the determination of earnings per share
Basic (in shares)	168,934,114	160,905,860
Diluted (in shares)	174,380,963	164,130,946

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Comprehensive income
Net income	$ 95.9	$ 138.3
Other comprehensive income (loss), net of tax
Change in foreign currency translation adjustment	(1.8)	(0.3)
Unrealized gains (losses) from debt securities held as available for sale investments	(18.4)	22.9
Reclassifications from accumulated other comprehensive loss	(0.3)	(0.6)
Total other comprehensive income (loss)	(20.5)	22
Comprehensive income	75.4	160.3
Net income attributable to noncontrolling interests	(1.1)	(2.4)
Comprehensive income available to SiriusPoint	$ 74.3	$ 157.9

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Parent	Preference shares Series B preference shares	Common shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss, net of tax	Change in foreign currency translation adjustment	Unrealized gains (losses) from debt securities held as available for sale investments	Noncontrolling interests
Balance, beginning of period at Dec. 31, 2022			$ 200	$ 16.2	$ 1,641.3	$ 262.2	$ (45)	$ (5.2)	$ (39.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preference shares, net			0
Issuance of common shares, net				0	0
Exercise of options				0	0
Share compensation					2.5
Change in ownership interest in subsidiary					(1.2)
Net income						138.3
Net income attributable to noncontrolling interests	$ (2.4)					(2.4)
Dividends on preference shares						(4)
Change in foreign currency translation adjustment	(0.3)							(0.3)
Unrealized gains (losses) from debt securities held as available for sale investments	22.9								22.9
Reclassifications from accumulated other comprehensive loss	(0.6)								(0.6)
Balance, end of period at Mar. 31, 2023	2,241.3	$ 2,229.9	200	16.2	1,642.6	394.1	(23)	(5.5)	(17.5)	$ 11.4
Balance, beginning of period at Dec. 31, 2023	2,530.6		200	16.8	1,693	601	3.1	(4.1)	7.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of preference shares, net			0
Issuance of common shares, net				0	0
Exercise of options				0.2	15.6
Share compensation					2.6
Change in ownership interest in subsidiary					0
Net income						95.9
Net income attributable to noncontrolling interests	(1.1)					(1.1)
Dividends on preference shares						(4)
Change in foreign currency translation adjustment	(1.8)							(1.8)
Unrealized gains (losses) from debt securities held as available for sale investments	(18.4)								(18.4)
Reclassifications from accumulated other comprehensive loss	(0.3)								(0.3)
Balance, end of period at Mar. 31, 2024	$ 2,620.4	$ 2,602.6	$ 200	$ 17	$ 1,711.2	$ 691.8	$ (17.4)	$ (5.9)	$ (11.5)	$ 17.8

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities
Net income	$ 95.9	$ 138.3
Adjustments to reconcile net income to net cash provided by operating activities:
Share compensation	4.1	5.6
Net realized and unrealized (gain) loss on investments and derivatives	4.7	(12.7)
Net realized and unrealized gain on investment in related party investment funds	0	(0.8)
Other revenues	15.9	25.1
Amortization of premium and accretion of discount, net	(18.3)	(20.2)
Amortization of intangible assets	2.9	2.4
Other items, net	(17.4)	(2.8)
Changes in assets and liabilities:
Insurance and reinsurance balances receivable, net	(160.1)	(376.9)
Deferred acquisition costs, net	(11.9)	(62.2)
Unearned premiums ceded	(45.6)	(113.5)
Loss and loss adjustment expenses recoverable, net	61.3	(15.8)
Deferred tax asset/liability	(16.9)	23.9
Other assets	(1.7)	(53.8)
Interest and dividends receivable	(2.2)	(6.8)
Loss and loss adjustment expense reserves	(42.8)	50.2
Unearned premium reserves	88.4	312
Deferred gain on retroactive reinsurance	(2.1)	0
Reinsurance balances payable	43.8	191.3
Accounts payable, accrued expenses and other liabilities	57.8	10.9
Net cash provided by operating activities	55.8	94.2
Investing activities
Purchases of investments	(977.1)	(1,259.4)
Proceeds from sales and maturities of investments	852.6	1,188.5
Proceeds from redemptions from related party investment funds	3	18.5
Change in due to/from brokers, net	43.7	58.5
Net cash provided by (used in) investing activities	(77.8)	6.1
Financing activities
Taxes paid on withholding shares	(1.5)	(3)
Proceeds from loans under an agreement to repurchase	0	2.3
Cash dividends paid to preference shareholders	(4)	(4)
Settlement of Contingent Value Rights	0	(38.5)
Net proceeds from exercise of options	15.6	0
Net proceeds (payments) on deposit liability contracts	(3)	3.8
Net cash provided by (used in) financing activities	7.1	(39.4)
Net increase (decrease) in cash, cash equivalents and restricted cash	(14.9)	60.9
Cash, cash equivalents and restricted cash at beginning of period	1,101.3	913.7
Cash, cash equivalents and restricted cash at end of period	$ 1,086.4	$ 974.6

Organization

Organization	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization 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 and services. These unaudited 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 consolidated balance sheet was derived from audited financial statements but does not include all disclosures required by U.S. GAAP. This Quarterly Report on Form 10-Q (“Form 10-Q”) 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, 2023 (the “2023 Form 10-K”) filed with the U.S. Securities and Exchange Commission on February 29, 2024. In the opinion of management, these unaudited 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. The results for the three months ended March 31, 2024 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, 2024
Accounting Policies [Abstract]
Significant accounting policies	2. Significant accounting policies There have been no material changes to the Company’s significant accounting policies as described in its 2023 Form 10-K. Recently issued accounting standards Issued and effective as of March 31, 2024 In June 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions (“ASU 2022-03”). The amendment clarifies the guidance in Topic 820 on the fair value measurement of an equity security that is subject to a contractual sale restriction and requires specific disclosures related to such an equity security. ASU 2022-03 is effective for public business entities for fiscal years beginning after December 15, 2023 and interim periods within those fiscal years. This pronouncement did not have a material impact on the Company’s consolidated financial statements. Issued but not yet effective as of March 31, 2024 Accounting pronouncements issued during the three months ended March 31, 2024 were either not relevant to the Company or did not impact the Company’s consolidated financial statements. Reclassifications and revisions Certain comparative figures have been reclassified to conform to the current year presentation in addition to the immaterial revisions to the financial statements as of and for the three months ended March 31, 2023 previously disclosed in the September 30, 2023 Form 10-Q.

Significant transactions

Significant transactions	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
Significant transactions	3. Significant transactions SiriusPoint International Loss Portfolio Transfer On March 2, 2023, the Company agreed, subject to applicable regulatory approvals and other closing conditions, to enter into a loss portfolio transfer transaction (“2023 LPT”), on a funds withheld basis, with Pallas Reinsurance Company Ltd., a subsidiary of the Compre Group, an insurance and reinsurance legacy specialist. The transaction covered loss reserves ceded initially estimated at $1.3 billion as of the valuation date of September 30, 2022, which were reduced to $905.6 million as of June 30, 2023 at closing, as a result of paid losses and favorable prior accident year reserve development recognized during the interim period, and included in Loss and loss adjustment expenses recoverable in the Company’s consolidated balance sheets. As of March 31, 2024, the Company recorded funds held payable of $702.5 million in Reinsurance balances payable and reinsurance recoverable of $725.1 million, and the Company’s estimate of deferred gain is $25.8 million. The 2023 LPT comprises several classes of business from 2021 and prior underwriting years. The aggregate limit under the 2023 LPT is 130% of roll forward reserves at the inception of the contract.

Segment reporting

Segment reporting	3 Months Ended
	Mar. 31, 2024
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 two operating segments: Reinsurance and Insurance & Services. The Company’s segments each have managers who are responsible for the overall profitability of their segments and who are directly accountable to the Company’s chief operating decision maker, the Chief Executive Officer ("CEO"). The CEO assesses segment operating performance, allocates capital, and makes resource allocation decisions based on Segment income (loss). The Company does not manage its assets by segment; accordingly, total assets are not allocated to the segments. Reinsurance In the Reinsurance segment, the Company provides reinsurance products to insurance and reinsurance companies, government entities, and other risk bearing vehicles on a treaty or facultative basis. For reinsurance assumed, the Company participates in the reinsurance market with a global focus through the broker market distribution channel. The Company primarily writes treaty reinsurance, on both a proportional and excess of loss basis, and provides facultative reinsurance in some of its business lines. In the United States and Bermuda, the Company’s core focus is on distribution, risk and clients located in North America, while our international operation is focused primarily on distribution, risks and clients located in Europe. The Reinsurance segment predominantly underwrites Casualty, Property and Specialty lines of business on a worldwide basis. Casualty – the Company provides reinsurance to casualty insurers who underwrite a diverse range of casualty classes. The Company works with clients all over the world, including multi-national, nationwide and regional carriers, as well as risk retention groups and captives. The Company also partners with managing general agents (“MGAs”) and sponsor cover holders. The Company’s underwriting focus is on proportional transactions covering all major commercial casualty lines, as well professional liability with an emphasis on specialty niche classes of business, including personal lines. Property – the Company works with leading global brokers as well as large national writers and regional companies. Underwriting is focused on providing critical catastrophe protection and worldwide coverage for natural perils, underwriting residential, commercial, and industrial risks in the United States, Europe and Asia. The Company’s property reinsurance offering includes: property catastrophe protection, risk excess of loss, cannabis - pro rata, building risk and structured property specifically in the United States. In 2023, as part of its International Reorganization, the Company significantly reduced its international property catastrophe premiums written, with reinsurance protection purchased at similar costs but with lower attachment points to further protect the balance sheet. Specialty - the Company’s business encompasses a broad range of worldwide reinsurance coverages, including proportional and excess of loss, treaty and facultative. Specialty business lines in the Reinsurance segment include Aviation & Space, Marine & Energy and Credit. Insurance & Services Through the Insurance & Services segment, the Company underwrites primary insurance in a number of sectors. The Insurance & Services segment includes Accident & Health, Casualty, and Specialty. Accident and Health (“A&H”) – the Company provides flexible insurance products to meet the risk management needs of diverse populations in select markets. This includes employer groups, associations, affinity groups, higher education and other niche markets. The Company also owns 100% of IMG and Armada, who receive fees for services provided within Insurance & Services and to third parties. IMG offers a full line of international medical insurance products, trip cancellation programs, medical management services and 24/7 emergency medical and travel assistance. Armada operates as a supplemental medical insurance MGA. Property & Casualty - the Company is a leading carrier for program administrators and managing general agents. The majority of its insurance business is written through partners in the property and casualty space, covering professional liability, workers’ compensation, and commercial auto lines in Bermuda, London, Europe, North America and round the world. Specialty - the Company’s business encompasses a broad range of worldwide insurance coverages. Specialty business lines in the Insurance & Services segment include Aviation & Space, Marine & Energy, Credit and Mortgage. Management uses segment income (loss) as the primary basis for assessing segment performance. Segment income (loss) is comprised of two components, underwriting income (loss) and net services income (loss). The Company calculates underwriting income (loss) by subtracting loss and loss adjustment expenses incurred, net, acquisition costs, net, and other underwriting expenses from net premiums earned. Net services income (loss) consists of services revenues (fee for service revenue), services expenses, and services non-controlling (income) loss. This definition of segment income (loss) aligns with how business performance is managed and monitored. We continue to evaluate our segments as our business evolves and may further refine our segments and segment income (loss) measures. Certain items are presented in a different manner for segment reporting purposes than in the consolidated statements of income. These items are reconciled to the consolidated presentation in the segment measure reclass column below. Included in Insurance & Services segment income (loss) are services noncontrolling loss (income) attributable to minority shareholders on non-wholly-owned subsidiaries. In addition, services revenues and services expenses are reconciled to other revenues and net corporate and other expenses, respectively. Segment results are shown prior to corporate eliminations. Corporate eliminations are included in the elimination column below as necessary to reconcile to underwriting income (loss), net services income (loss), and segment income (loss) to the consolidated statements of income. Corporate includes the results of all runoff business, which represents certain classes of business that we no longer actively underwrite, including the effect of the Restructuring Plan and certain reinsurance contracts that have interest crediting features. Corporate results also include asbestos and environmental and other latent liability exposures on a gross basis, which have mostly been ceded, as well as specific workers’ compensation and cyber programs which the Company no longer writes. In addition, revenue and expenses managed at the corporate level, including realized gains (losses), other investment income, including gains (losses) from strategic investments, net realized and unrealized investment gains (losses) from related party investment funds, non services-related other revenues, non services-related net corporate and other expenses, intangible asset amortization, interest expense, foreign exchange (gains) losses and income tax (expense) benefit are reported within Corporate. The CEO does not manage segment results or allocate resources to segments when considering these items and they are therefore excluded from our definition of segment income (loss). The following is a summary of the Company’s operating segment results for the three months ended March 31, 2024 and 2023: Three months ended March 31, 2024 Reinsurance Insurance & Services Core Eliminations (2) Corporate Segment Measure Reclass Total Gross premiums written $ 356.4 $ 524.3 $ 880.7 $ — $ 25.9 $ — $ 906.6 Net premiums written 290.1 337.1 627.2 — 12.1 — 639.3 Net premiums earned 253.6 264.2 517.8 — 76.0 — 593.8 Loss and loss adjustment expenses incurred, net 124.6 176.5 301.1 (1.4) 17.8 — 317.5 Acquisition costs, net 69.8 65.2 135.0 (33.2) 43.1 — 144.9 Other underwriting expenses 19.3 18.1 37.4 — 4.4 — 41.8 Underwriting income 39.9 4.4 44.3 34.6 10.7 — 89.6 Services revenues — 65.8 65.8 (37.1) — (28.7) — Services expenses — 46.0 46.0 — — (46.0) — Net services fee income — 19.8 19.8 (37.1) — 17.3 — Services noncontrolling income — (1.7) (1.7) — — 1.7 — Net services income — 18.1 18.1 (37.1) — 19.0 — Segment income 39.9 22.5 62.4 (2.5) 10.7 19.0 89.6 Net investment income 78.8 — 78.8 Net realized and unrealized investment gains 1.0 — 1.0 Other revenues (16.8) 28.7 11.9 Net corporate and other expenses (10.0) (46.0) (56.0) Intangible asset amortization (2.9) — (2.9) Interest expense (20.5) — (20.5) Foreign exchange gains 3.7 — 3.7 Income before income tax expense $ 39.9 $ 22.5 62.4 (2.5) 44.0 1.7 105.6 Income tax expense — — (9.7) — (9.7) Net income 62.4 (2.5) 34.3 1.7 95.9 Net (income) loss attributable to noncontrolling interests — — 0.6 (1.7) (1.1) Net income available to SiriusPoint $ 62.4 $ (2.5) $ 34.9 $ — $ 94.8 Underwriting Ratios: (1) Loss ratio 49.1 % 66.8 % 58.1 % 53.5 % Acquisition cost ratio 27.5 % 24.7 % 26.1 % 24.4 % Other underwriting expenses ratio 7.6 % 6.9 % 7.2 % 7.0 % Combined ratio 84.2 % 98.4 % 91.4 % 84.9 % (1) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (2) Insurance & Services MGAs recognize fees for service using revenue from contracts with customers accounting standards, whereas insurance companies recognize acquisition expenses using insurance contract accounting standards. While ultimate revenues and expenses recognized will match, there will be recognition timing differences based on the different accounting standards. Three months ended March 31, 2023 Reinsurance Insurance & Services Core Eliminations (2) Corporate Segment Measure Reclass Total Gross premiums written $ 396.2 $ 664.0 $ 1,060.2 $ — $ 50.3 $ — $ 1,110.5 Net premiums written 311.0 452.6 763.6 — 28.1 — 791.7 Net premiums earned 259.5 291.2 550.7 — 44.8 — 595.5 Loss and loss adjustment expenses incurred, net 85.6 172.5 258.1 (1.3) 10.3 — 267.1 Acquisition costs, net 66.0 71.7 137.7 (32.5) 14.5 — 119.7 Other underwriting expenses 28.2 19.3 47.5 — 4.7 — 52.2 Underwriting income 79.7 27.7 107.4 33.8 15.3 — 156.5 Services revenues 0.2 63.6 63.8 (34.3) — (29.5) — Services expenses — 45.5 45.5 — — (45.5) — Net services fee income 0.2 18.1 18.3 (34.3) — 16.0 — Services noncontrolling income — (1.6) (1.6) — — 1.6 — Net services income 0.2 16.5 16.7 (34.3) — 17.6 — Segment income 79.9 44.2 124.1 (0.5) 15.3 17.6 156.5 Net investment income 61.7 — 61.7 Net realized and unrealized investment gains 11.3 — 11.3 Net realized and unrealized investment gains from related party investment funds 0.8 — 0.8 Other revenues (20.7) 29.5 8.8 Net corporate and other expenses (14.5) (45.5) (60.0) Intangible asset amortization (2.4) — (2.4) Interest expense (12.8) — (12.8) Foreign exchange losses (0.1) — (0.1) Income before income tax expense $ 79.9 $ 44.2 124.1 (0.5) 38.6 1.6 163.8 Income tax expense — — (25.5) — (25.5) Net income 124.1 (0.5) 13.1 1.6 138.3 Net income attributable to noncontrolling interests — — (0.8) (1.6) (2.4) Net income available to SiriusPoint $ 124.1 $ (0.5) $ 12.3 $ — $ 135.9 Underwriting Ratios: (1) Loss ratio 33.0 % 59.2 % 46.9 % 44.9 % Acquisition cost ratio 25.4 % 24.6 % 25.0 % 20.1 % Other underwriting expenses ratio 10.9 % 6.6 % 8.6 % 8.8 % Combined ratio 69.3 % 90.4 % 80.5 % 73.8 % (1) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (2) Insurance & Services MGAs recognize fees for service using revenue from contracts with customers accounting standards, whereas insurance companies recognize acquisition expenses using insurance contract accounting standards. While ultimate revenues and expenses recognized will match, there will be recognition timing differences based on the different accounting standards.

Cash, cash equivalents, restric

Cash, cash equivalents, restricted cash and restricted investments	3 Months Ended
	Mar. 31, 2024
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, 2024 and December 31, 2023: March 31, December 31, Cash and cash equivalents $ 867.5 $ 969.2 Restricted cash securing letter of credit facilities (1) 70.2 56.9 Restricted cash securing reinsurance contracts (2) 119.6 52.7 Restricted cash held by managing general underwriters 29.1 22.5 Total cash, cash equivalents and restricted cash (3) 1,086.4 1,101.3 Restricted investments securing reinsurance contracts and letter of credit facilities (1) (2) (4) 2,658.5 2,668.0 Total cash, cash equivalents, restricted cash and restricted investments $ 3,744.9 $ 3,769.3 (1) Restricted cash and restricted investments 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, short-term investments 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 consolidated statements of cash flows. (4) Restricted investments include required deposits with certain insurance state regulatory agencies in order to maintain insurance licenses.

Fair value measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair value measurements	6. 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, 2024 and December 31, 2023: March 31, 2024 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 1,044.0 $ — $ 1,044.0 Residential mortgage-backed securities — 926.8 — 926.8 Commercial mortgage-backed securities — 236.5 — 236.5 Corporate debt securities — 1,730.8 — 1,730.8 U.S. government and government agency 1,066.6 2.9 — 1,069.5 Non-U.S. government and government agency — 49.9 — 49.9 Total debt securities, available for sale 1,066.6 3,990.9 — 5,057.5 Asset-backed securities — 199.7 — 199.7 Residential mortgage-backed securities — 55.3 — 55.3 Commercial mortgage-backed securities — 66.2 — 66.2 Corporate debt securities — 41.5 — 41.5 U.S. government and government agency 33.4 — — 33.4 Non-U.S. government and government agency — 9.9 — 9.9 Total debt securities, trading 33.4 372.6 — 406.0 Total equity securities 1.6 — — 1.6 Short-term investments 295.2 34.7 — 329.9 Other long-term investments — — 170.6 170.6 Derivative assets — — 1.4 1.4 $ 1,396.8 $ 4,398.2 $ 172.0 5,967.0 Cost and equity method investments 73.6 Investments in funds valued at NAV 158.0 Total assets $ 6,198.6 Liabilities Liability-classified capital instruments $ — $ — $ 83.2 $ 83.2 Derivative liabilities — — 20.6 20.6 Total liabilities $ — $ — $ 103.8 $ 103.8 December 31, 2023 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 880.7 $ — $ 880.7 Residential mortgage-backed securities — 902.8 — 902.8 Commercial mortgage-backed securities — 204.1 — 204.1 Corporate debt securities — 1,573.1 — 1,573.1 U.S. government and government agency 1,132.6 4.1 — 1,136.7 Non-U.S. government and government agency — 58.0 — 58.0 Total debt securities, available for sale 1,132.6 3,622.8 — 4,755.4 Asset-backed securities — 256.6 — 256.6 Residential mortgage-backed securities — 57.2 — 57.2 Commercial mortgage-backed securities — 67.8 — 67.8 Corporate debt securities — 45.2 — 45.2 U.S. Government and government agency 98.1 — — 98.1 Non-U.S. government and government agency — 10.0 — 10.0 Total debt securities, trading 98.1 436.8 — 534.9 Total equity securities 1.6 — — 1.6 Short-term investments 321.9 49.7 — 371.6 Other long-term investments — — 169.7 169.7 Derivative assets — — 15.7 15.7 $ 1,554.2 $ 4,109.3 $ 185.4 5,848.9 Cost and equity method investments 80.1 Investments in funds valued at NAV 164.3 Total assets $ 6,093.3 Liabilities Securities sold under an agreement to repurchase $ — $ — $ 67.3 $ 67.3 Derivative liabilities — — 6.4 6.4 Total liabilities $ — $ — $ 73.7 $ 73.7 During the three months ended March 31, 2024, the Company did not reclassify its assets or liabilities between Levels 2 and 3 (December 31, 2023 - no reclassifications). Valuation techniques The Company uses independent 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 independent pricing services to determine fair value. 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 independent 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 debt securities and short-term 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 independent 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 independent pricing services. When evaluating these securities, the independent 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 independent 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 independent pricing services. When evaluating these securities, the independent 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 independent 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 independent 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 independent 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. Short-term investments Short-term investments consist of U.S. treasury bills, certificates of deposit and other securities, which, at the time of purchase, mature within a period of greater than three months but less than one year. These investments are generally priced by independent pricing services using the techniques described for U.S. government and government agency securities and Corporate debt securities described above. 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 monthly, quarterly, or semi-annual partnership capital statements primarily with a one or three 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. 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. 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. For strategic investments carried at fair value, management either engages a third-party valuation specialist to assist in determination of the fair value based on commonly accepted valuation methods (i.e., income approach, market approach) as of the valuation date or performs valuation internally. In addition, investors fair value analyses prepared by third party valuation specialists working with Strategic Investment operating management are referenced where available. Where criteria to be accounted for under the equity method is not met, we have elected to value our strategic investments at the cost adjusted for market observable events less impairment method, a measurement alternative in which the investment is measured at cost and remeasured to fair value when determined to be impaired or upon observable transactions prices becoming available. See Note 9 for additional information on the fair values of derivative financial instruments used for both risk management and investment purposes. Underwriting-related derivatives 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 tables present the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2024 and 2023: January 1, 2024 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2024 Assets Other long-term investments $ 169.7 $ — $ — $ — $ 0.9 $ 170.6 Derivative assets 15.7 — — (4.6) (9.7) 1.4 Total assets $ 185.4 $ — $ — $ (4.6) $ (8.8) $ 172.0 Liabilities Liability-classified capital instruments $ (67.3) $ — $ — $ — $ (15.9) $ (83.2) Derivative liabilities (6.4) — — (1.1) (13.1) (20.6) Total liabilities $ (73.7) $ — $ — $ (1.1) $ (29.0) $ (103.8) January 1, 2023 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2023 Assets Preferred stocks $ 3.2 $ — $ — $ — $ — $ 3.2 Other long-term investments 227.3 — 0.4 — (0.3) 227.4 Derivative assets 9.5 — 2.5 (2.1) 1.4 11.3 Total assets $ 240.0 $ — $ 2.9 $ (2.1) $ 1.1 $ 241.9 Liabilities Liability-classified capital instruments $ (21.4) $ — $ — $ — $ (25.6) $ (47.0) Derivative liabilities (8.6) — (3.2) 1.5 1.9 (8.4) Total liabilities $ (30.0) $ — $ (3.2) $ 1.5 $ (23.7) $ (55.4) (1) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in total net investment income and realized and unrealized investment gains in the consolidated statements of income. 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 consolidated statements of income. 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. The following table includes financial instruments for which the carrying value differs from the estimated fair values at March 31, 2024 and December 31, 2023. The fair values of the below financial instruments are based on observable inputs and are considered Level 2 measurements. March 31, 2024 December 31, 2023 Fair Value Carrying Value Fair Value Carrying Value 2017 SEK Subordinated Notes $ 214.0 $ 252.6 $ 206.6 $ 267.9 2016 Senior Notes 382.0 403.2 370.0 403.5 2015 Senior Notes 113.9 114.8 115.2 114.8 Series B preference shares $ 202.6 $ 200.0 $ 197.4 $ 200.0

Investments

Investments	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	7. 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 available for sale, debt securities held for trading, short-term investments, equity securities, and other long-term investments which are classified as trading securities with the exception of debt securities held as available for sale. Realized investment gains and losses on debt securities are reported in pre-tax revenues. Unrealized investment gains and losses on debt securities are reported based on classification. Trading securities flow through pre-tax revenues, whereas securities classified as available for sale (“AFS”) flow through other comprehensive income. For debt securities classified as AFS for which a decline in the fair value between the amortized cost is due to credit-related factors, an allowance is established for the difference between the estimated recoverable value and amortized cost with a corresponding impact to the consolidated statements of income. The allowance is limited to the difference between amortized cost and fair value. A credit losses impairment assessment is performed on securities using both quantitative and qualitative factors. Qualitative factors include significant declines in fair value below amortized cost. Additionally, a qualitative assessment is also performed over debt securities to evaluate potential credit losses. Examples of qualitative indicators include issuer credit downgrades as well as changes to credit spreads. Declines in fair value related to a debt security that do not relate to a credit loss are recorded as a component of accumulated other comprehensive income. Debt securities The following tables provide the cost or amortized cost, gross unrealized investment gains (losses), net foreign currency March 31, 2024 Cost or Gross Gross Net foreign Fair value Debt securities, available for sale Asset-backed securities $ 1,040.7 $ 9.5 $ (6.2) $ — $ 1,044.0 Residential mortgage-backed securities 930.9 12.9 (17.0) — 926.8 Commercial mortgage-backed securities 236.9 1.4 (1.8) — 236.5 Corporate debt securities 1,739.4 5.9 (14.1) (0.4) 1,730.8 U.S. government and government agency 1,077.0 1.7 (9.2) — 1,069.5 Non-U.S. government and government agency 50.5 — (0.4) (0.2) 49.9 Total debt securities, available for sale (1) $ 5,075.4 $ 31.4 $ (48.7) $ (0.6) $ 5,057.5 Debt securities, trading Asset-backed securities $ 203.0 $ 0.6 $ (3.9) $ — $ 199.7 Residential mortgage-backed securities 64.1 — (8.8) — 55.3 Commercial mortgage-backed securities 73.2 0.1 (7.1) — 66.2 Corporate debt securities 48.7 — (7.2) — 41.5 U.S. government and government agency 34.1 — (0.7) — 33.4 Non-U.S. government and government agency 10.2 — (0.3) — 9.9 Total debt securities, trading $ 433.3 $ 0.7 $ (28.0) $ — $ 406.0 December 31, 2023 Cost or Gross Gross Net foreign Fair value Debt securities, available for sale Asset-backed securities $ 882.2 $ 7.8 $ (9.3) $ — $ 880.7 Residential mortgage-backed securities 903.0 15.8 (16.0) — 902.8 Commercial mortgage-backed securities 204.0 1.6 (1.5) — 204.1 Corporate debt securities 1,569.6 12.0 (7.5) (1.0) 1,573.1 U.S. government and government agency 1,137.8 5.5 (6.6) — 1,136.7 Non-U.S. government and government agency 58.0 0.2 (0.3) 0.1 58.0 Total debt securities, available for sale (1) $ 4,754.6 $ 42.9 $ (41.2) $ (0.9) $ 4,755.4 Debt securities, trading Asset-backed securities $ 261.1 $ 0.6 $ (5.1) $ — $ 256.6 Residential mortgage-backed securities 67.0 — (9.8) — 57.2 Commercial mortgage-backed securities 76.7 0.1 (9.0) — 67.8 Corporate debt securities 52.2 — (7.0) — 45.2 U.S. government and government agency 100.8 — (2.7) — 98.1 Non-U.S. government and government agency 10.3 — (0.3) — 10.0 Total debt securities, trading $ 568.1 $ 0.7 $ (33.9) $ — $ 534.9 (1) As of March 31, 2024 and December 31, 2023, the Company did not record an allowance for credit losses on the AFS portfolio. As of March 31, 2024, 735 unique debt securities classified as AFS were in a gross unrealized loss position for greater than 12 months with a market value of $542.3 million and an unrealized loss of $20.0 million (December 31, 2023 - 713 unique debt securities classified as AFS were in a gross unrealized loss position for greater than 12 months with a market value of $556.9 million and an unrealized loss of $20.3 million). The weighted average duration of the Company's debt securities, net of short positions in U.S. treasuries, as of March 31, 2024 was approximately 2.9 years, including short-term investments (December 31, 2023 - approximately 2.8 years). The following table provides the cost or amortized cost and fair value of the Company's debt securities bifurcated into debt securities held for trading and AFS as of March 31, 2024 and December 31, 2023 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, 2024 December 31, 2023 Debt securities, AFS Debt securities, trading Debt securities, AFS Debt securities, trading Cost or Fair value Cost or Fair value Cost or Fair value Cost or Fair value Due in one year or less $ 460.3 $ 457.7 $ 14.2 $ 14.0 $ 358.6 $ 357.2 $ 80.2 $ 79.7 Due after one year through five years 2,131.5 2,116.0 32.9 32.2 2,221.0 2,219.8 37.2 34.5 Due after five years through ten years 272.4 274.2 19.4 17.9 183.3 188.5 19.4 18.0 Due after ten years 2.7 2.3 26.5 20.8 2.5 2.3 26.6 21.3 Mortgage-backed and asset-backed securities 2,208.5 2,207.3 340.3 321.1 1,989.2 1,987.6 404.7 381.4 Total debt securities $ 5,075.4 $ 5,057.5 $ 433.3 $ 406.0 $ 4,754.6 $ 4,755.4 $ 568.1 $ 534.9 The following table summarizes the ratings and fair value of debt securities held in the Company's investment portfolio as of March 31, 2024 and December 31, 2023. Credit ratings are assigned based on ratings provided by nationally recognized statistical rating organizations. March 31, 2024 December 31, 2023 Debt securities, AFS Debt securities, trading Debt securities, AFS Debt securities, trading AAA $ 796.6 $ 197.4 $ 730.4 $ 248.4 AA 2,378.8 110.1 2,334.4 177.0 A 1,312.2 19.3 1,122.1 28.9 BBB 485.5 70.9 515.5 71.7 Other 84.4 8.3 53.0 8.9 Total debt securities $ 5,057.5 $ 406.0 $ 4,755.4 $ 534.9 As of March 31, 2024, the above totals included $192.5 million of sub-prime securities. Of this total, $101.3 million was rated AAA, $57.9 million rated AA, $5.7 million rated A, $17.8 million rated BBB and $9.8 million were unrated. As of December 31, 2023, the above totals included $185.1 million of sub-prime securities. Of this total, $117.5 million were rated AAA, $37.7 million rated AA, $12.3 million rated A, $13.3 million rated BBB and $4.3 million were unrated. 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, 2024 and December 31, 2023 were as follows: Cost or Gross Gross Net foreign Fair value March 31, 2024 Equity securities $ 1.6 $ — $ (0.2) $ 0.2 $ 1.6 Other long-term investments $ 343.1 $ 20.7 $ (70.3) $ 3.1 $ 296.6 December 31, 2023 Equity securities $ 1.9 $ — $ (0.5) $ 0.2 $ 1.6 Other long-term investments $ 356.2 $ 20.0 $ (70.1) $ 2.4 $ 308.5 The Company holds investments in hedge funds and private equity funds, which are included in other long-term investments. The carrying value of other long-term investments as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Hedge funds and private equity funds (1) $ 70.1 $ 74.5 Strategic investments (2) 196.4 203.9 Other investments (2) 30.1 30.1 Total other long-term investments $ 296.6 $ 308.5 (1) Incl udes $52.2 million of investments carried at NAV (December 31, 2023 - $58.7 million) and no investments classified as Level 3 (December 31, 2023 - no investments classified as Level 3) within the fair value hierarchy. (2) As of March 31, 2024, the Company had $12.1 million of unfunded commitments relating to these investments ( December 31, 2023 - $14.7 million). The Company’s other long-term investments may be accounted for under either the equity method (“equity method investments”) or the fair value option (“equity method eligible unconsolidated entities”). The following table presents the components of other long-term investments as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Equity method eligible unconsolidated entities, using the fair value option $ 139.0 $ 139.2 Equity method investments 40.9 37.0 Other unconsolidated investments, at fair value (1) 84.0 89.2 Other unconsolidated investments, at cost (2) 32.7 43.1 Total other long-term investments $ 296.6 $ 308.5 (1) Includes other long-term investments that are not equity method eligible and are measured at fair value. (2) The Company has elected to apply the cost adjusted for market observable events impairment measurement alternative to investments that do not meet the criteria to be accounted for under the equity method, in which the investment is measured at cost and remeasured to fair value when impaired or upon observable transaction prices. Equity method eligible unconsolidated entities, using the fair value option, exclude the Company’s investment in Third Point Enhanced LP (“ TP Enhanced Fund ”), Third Point Venture Offshore Fund I LP (“TP Venture Fund”), Third Point Venture Offshore Fund II LP (“TP Venture Fund II”), collectively, the “Related Party Investment Funds.” Refer to “Investments in related party investment funds” discussed below. Investments in related party investment funds The following table provides the fair value of the Company's investments in related party investment funds as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Third Point Enhanced LP $ 77.8 $ 77.5 Third Point Venture Offshore Fund I LP 24.7 25.0 Third Point Venture Offshore Fund II LP 3.1 3.1 Investments in related party investment funds, at fair value $ 105.6 $ 105.6 Investment in Third Point Enhanced LP On February 23, 2022, the Company entered into the Fourth Amended and Restated Exempted Limited Partnership Agreement of Third Point Enhanced LP with Third Point Advisors LLC (“TP GP”) and the other parties thereto (the “2022 LPA”). In accordance with the 2022 LPA, TP GP services as the general partner of the TP Enhanced Fund. For further details with respect to the 2022 LPA, please refer to Note 8 “Investments” of Part II, Item 8. “Financial Statements and Supplementary Data” included in the 2023 Form 10-K. 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. As of March 31, 2024, the Company had no unfunded commitments related to TP Enhanced Fund . Investment in Third Point Venture Offshore Fund I LP On March 1, 2021, SiriusPoint Bermuda entered into the Amended and Restated Exempted Limited Partnership Agreement (“2021 Venture LPA”) of 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 co mpanies, primarily in the expansion through late/pre-IPO stage. The TP Venture Fund may also invest in early stage companies. Due to 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, 2024, the Company had $9.5 million of unfunded commitments related to TP Venture Fund . As of March 31, 2024, the Company holds interests of approximately 16.8% of the net asset value of TP Venture Fund . Investment in Third Point Venture Offshore Fund II LP On June 30, 2022, SiriusPoint Bermuda entered into the Amended and Restated Exempted Limited Partnership Agreement (“2022 Venture II LPA”) of TP Venture Fund II. In accordance with the 2022 Venture II LPA, Third Point Venture GP II LLC (“TP Venture GP II”) serves as the general partner of TP Venture Fund II. The TP Venture Fund II 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, 2024, the Company had $21.6 million of unfunded commitments related to TP Venture Fund II. As of March 31, 2024, the Company holds interests of approximately 17.8% of the net asset value of TP Venture Fund II .

Total net investment income and

Total net investment income and realized and unrealized investment gains	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Total net investment income and realized and unrealized investment gains	8. Total net investment income and realized and unrealized investment gains Net investment income and net realized and unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, available for sale $ 63.7 $ 35.1 Debt securities, trading 8.8 29.1 Short-term investments 4.4 8.4 Other long-term investments 0.5 4.4 Derivative instruments 1.3 — Net realized and unrealized investment gains from related party investment funds — 0.8 Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents 78.7 77.8 Investment expenses (3.9) (5.4) Net investment income on cash and cash equivalents 5.0 1.4 Total net investment income and realized and unrealized gains on investments $ 79.8 $ 73.8 Net realized and unrealized gains on investments Net realized and unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Gross realized gains $ 5.5 $ 5.8 Gross realized losses (9.2) (15.6) Net realized losses on investments (3.7) (9.8) Net unrealized gains on investments 4.7 21.1 Net realized and unrealized gains on investments (1)(2) $ 1.0 $ 11.3 (1) Excludes realized and unrealized gains on the Company’s investments in related party investment funds and unrealized gains (losses) from available for sale investments, net of tax. (2) Includes net realized and unrealized gains (losses) of $(1.9) million from related party investments included in other-long term investments for the three months ended March 31, 2024 (2023 - $1.8 million). Net realized investment losses Net realized investment losses for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, available for sale $ (0.3) $ (0.6) Debt securities, trading (3.4) (7.4) Short-term investments 0.6 (0.2) Other long-term investments (0.8) (0.4) Net investment income (loss) on cash and cash equivalents 0.2 (1.2) Net realized investment losses $ (3.7) $ (9.8) Net realized investment losses on Other long-term investments for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Hedge funds and private equity funds $ 1.0 $ (0.4) Strategic investments (1.8) — Net realized investment losses on Other long-term investments $ (0.8) $ (0.4) Net unrealized investment gains Net unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, trading $ 5.4 $ 23.0 Short-term investments (0.9) (0.4) Derivative instruments 1.0 — Other long-term investments 1.3 (3.0) Net investment income (loss) on cash and cash equivalents (2.1) 1.5 Net unrealized investment gains $ 4.7 $ 21.1 Net unrealized investment gains (losses) on Other long-term investments for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Hedge funds and private equity funds $ (0.6) $ 0.9 Strategic investments 1.9 (3.9) Net unrealized investment gains (losses) on Other long-term investments $ 1.3 $ (3.0) The following table summarizes the amount of total gains (losses) included in earnings attributable to unrealized investment gains (losses) – Level 3 investments for the three months ended March 31, 2024 and 2023: 2024 2023 Debt securities, trading $ — $ 0.1 Other long-term investments 1.1 (4.8) Total unrealized investment gains (losses) – Level 3 investments $ 1.1 $ (4.7)

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	9. Derivatives The Company holds derivatives for both risk management and investment purposes. Foreign currency exchange rate derivatives The Company executes foreign currency forwards, swaps, and futures to manage foreign currency exposure. The foreign currency exchange rate derivatives are not designated or accounted for under hedge accounting. 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. As of March 31, 2024, the Company pledged $42.0 million in securities collateral associated with the foreign currency derivatives (December 31, 2023 - $42.2 million). These securities are included in debt securities, available for sale, in the Company’s consolidated balance sheets. Weather derivatives The Company holds assets and assumes liabilities related to weather and weather contingent risk management products. Weather and weather contingent derivative contracts are entered into with the objective of generating profits in normal climatic conditions. Accordingly, the Company’s weather and weather contingent derivatives are not designed to meet the criteria for hedge accounting under U.S. GAAP. The Company receives payment of premium at the contract inception in exchange for bearing the risk of variations in a quantifiable weather index. Management uses available market data and intern al pricing models based upon consistent statistical methodologies to estimate the fair value. Because of the significance of the unobservable inputs used to estimate the fair value of the Company's weather risk contracts, the fair value measurements of the contracts are deemed to be Level 3 measurements in the fair value hierarchy as of March 31, 2024. The Company does not provide or hold any collateral associated with the weather derivatives. Credit default swap Credit default swaps protect the buyer against the loss of principal on one or more underlying bonds, loans, or mortgages in the event the issuer suffers a credit event. The Company provides its client with protection against financial non-performance of a subsidiary. The fair value of the swap is estimated using a single broker quote, and accordingly, is classified as a Level 3 measurement. As of March 31, 2024, the Company pledged $20.5 million in securities collateral associated with the credit default swap (December 31, 2023 - $22.3 million). These securities are included in debt securities, available for sale, in the Company’s consolidated balance sheets. 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 consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Derivatives not designated as hedging instruments Derivative assets at fair value (1) Derivative liabilities at fair value (2) Notional Derivative assets at fair value (1) Derivative liabilities at fair value (2) Notional Foreign currency forwards $ 1.1 $ 6.9 $ 808.6 $ 12.0 $ — $ 585.3 Weather derivatives 0.1 5.1 20.4 0.2 1.0 30.6 Interest rate swaps 0.1 — 62.7 3.4 1.7 62.7 Credit default swap 0.1 — 30.0 0.1 — 30.0 Reinsurance contracts accounted for as derivatives $ — $ 8.6 $ 94.3 $ — $ 3.7 $ 97.4 (1) Derivative assets are classified within other assets in the Company’s consolidated balance sheets . (2) Derivative liabilities are classified within accounts payable, accrued expenses and other liabilities in the Company’s consolidated balance sheets. The following table summarizes information on the classification and net impact on earnings, recognized in the Company’s consolidated statements of income relating to derivatives during the three months ended March 31, 2024 and 2023: Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings 2024 2023 Foreign currency forwards Foreign exchange (gains) losses $ (17.4) $ (1.6) Weather derivatives Other revenues (1.5) 3.5 Foreign currency swaps Foreign exchange (gains) losses — (1.6) Interest rate swaps Net realized and unrealized investment gains 1.3 — Reinsurance contracts accounted for as derivatives Other revenues $ (4.8) $ 0.1

Variable and voting interest en

Variable and voting interest entities	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable and voting interest entities	10. Variable and voting 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 Alstead Reinsurance Ltd. (“Alstead Re”) is considered a VIE and the C ompany has concluded that it is the primary beneficia ry of Alstead Re because the Company can exercise control over the activities that most significantly impact the economic performance of Alstead Re. As a result, the Company has consolidated the results of Alstead Re in its consolidated financial statements. As of March 31, 2024, Alstead Re’s assets and liabilities included in the Company’s consolidated balance sheets were $14.7 million and $9.4 million, respectively (December 31, 2023 - $14.5 million and $9.2 million, respectively). Arcadian Arcadian Risk Capital Ltd. (“Arcadian”) is considered a VIE and the Company has concluded that it is the primary beneficiary of Arcadian because the Company can exercise control 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 consolidated financial statements. The Company’s ownership in Arcadian as of March 31, 2024 was 49%, and its 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, 2024 , Arcadian’s assets and liabilities, before intercompany eliminations, included in the Company’s consolidated bala nce sheets were $142.9 million and $113.5 million, respectively (December 31, 2023 - $150.9 million and $123.8 million, respectively) . Banyan In January 2023, Banyan Risk Ltd. (“Banyan”) completed a recapitalization in which the Company’s ownership decreased from 100% to 49%. After the recapitalization, Banyan was considered a VIE and the Company was its primary beneficiary as it could exercise control over the activities that most significantly impacted the economic performance of Banyan. The Company consolidated the results of Banyan in its consolidated financial statements through September 30, 2023. In October 2023, the Company sold the remainder of its ownership to Banyan and deconsolidated upon sale effective October 1, 2023. Consolidated voting interest entities Alta Signa Alta Signa Holdings (“Alta Signa”) is considered a VOE and the Company holds a majority of the voting interests through its seats on Alta Signa’s board of directors. As a result, the Company has consolidated the results of Alta Signa in its consolidated financial statements. The Company’s ownership in Alta Signa as of March 31, 2024 was 75.1%. As of March 31, 2024, Alta Signa’s assets and liabilities, before intercompany eliminations, included in the Company’s consolidated balance sheets were $3.2 million and $0.7 million, respectively (December 31, 2023 - $2.8 million and $0.8 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, 2024 and 2023: 2024 2023 Balance, beginning of period $ 16.7 $ 7.9 Net income attributable to noncontrolling interests 1.1 2.4 Contributions — 1.1 Balance, end of period $ 17.8 $ 11.4 Non-consolidated variable interest entities T he 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, 2024 and December 31, 2023: Maximum Exposure to Loss Total VIE Assets On-Balance Sheet Off-Balance Sheet Total March 31, 2024 Other long-term investments (1) $ 175.8 $ 126.2 $ 1.9 $ 128.1 December 31, 2023 Other long-term investments (1) $ 189.8 $ 126.2 $ 5.7 $ 131.9 (1) Excludes the Company’s investments in Related Party Investment Funds which are also VIEs and are discussed separately below. Third Point Enhanced LP As of March 31, 2024, the Company and TP GP hold interests of approximately 89.3% and 10.7%, 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 the TP Enhanced Fund. See Note 7 for additional information on the Company’s investment in the TP Enhanced Fund. Investment in Third Point Venture Offshore Fund I LP TP Venture GP controls all of the investment decision-making authority of the TP Venture Fund. The Company does not have the power to direct the activities which most significantly impact the economic performance of the TP Venture Fund . The Company’s maximum exposure to loss corresponds to the value of its investment in the TP Venture Fund . See Note 7 for additional information on the Company’s investment in the TP Venture Fund. Investment in Third Point Venture Offshore Fund II LP TP Venture GP II controls all of the investment decision-making authority of the TP Venture Fund II. The Company does not have the power to direct the activities which most significantly impact the economic performance of the TP Venture Fund II. The Company’s maximum exposure to loss corresponds to the value of its investment in TP Venture Fund II. See Note 7 for additional information on the Company’s investment in TP Venture Fund II .

Loss and loss adjustment expens

Loss and loss adjustment expense reserves	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
Loss and loss adjustment expense reserves	11. 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, 2024 and 2023: 2024 2023 Gross reserves for loss and loss adjustment expenses, beginning of period $ 5,608.1 $ 5,268.7 Less: loss and loss adjustment expenses recoverable, beginning of period (2,295.1) (1,376.2) Less: deferred charges on retroactive reinsurance contracts 27.5 (1.0) Net reserves for loss and loss adjustment expenses, beginning of period 3,340.5 3,891.5 Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in: Current year 356.4 372.5 Prior years (38.9) (105.4) Total incurred loss and loss adjustment expenses 317.5 267.1 Net loss and loss adjustment expenses paid in respect of losses occurring in: Current year (44.0) (36.4) Prior years (272.8) (202.1) Total net paid losses (316.8) (238.5) Foreign currency translation 15.8 6.0 Net reserves for loss and loss adjustment expenses, end of period 3,357.0 3,926.1 Plus: loss and loss adjustment expenses recoverable, end of period 2,233.8 1,392.0 Plus: deferred (gains) charges on retroactive reinsurance (1) (25.5) 0.8 Gross reserves for loss and loss adjustment expenses, end of period $ 5,565.3 $ 5,318.9 (1) Deferred charges on retroactive reinsurance are recorded in other assets on the Company’s consolidated balance sheets. Deferred gains on retroactive reinsurance are presented as a separate line item on the Company’s consolidated balance sheets. The Company's prior year reserve development arises from changes to estimates of losses and loss adjustment expenses related to loss events that occurred in previous calendar years. For the three months ended March 31, 2024, the Company recorded $38.9 million of net favorable prior year loss reserve development primarily resulting from favorable development on one contract in runoff, as well as decreased ultimate losses in the credit reinsurance portfolio. For the three months ended March 31, 2023 , the Company recorded $105.4 million of net favorable prior year loss reserve development primarily resulting from decreases in the domestic and international property and casualty lines of business in the Reinsurance segment and A&H in the Insurance & Services segment, driven by reserving analyses performed in connection with the 2023 LPT.

Allowance for expected credit l

Allowance for expected credit losses	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
Allowance for expected credit losses	12. Allowance for expected credit losses The Company is exposed to credit losses 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, Standard & Poor's (“S&P”), Fitch Ratings, Demotech). 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, 2024 and December 31, 2023 are as follows: March 31, 2024 December 31, 2023 Insurance and reinsurance balances receivable, net $ 2,127.2 $ 1,966.3 Loss and loss adjustment expenses recoverable, net 2,233.8 2,295.1 Other assets (1) 84.6 76.8 Total assets in scope $ 4,445.6 $ 4,338.2 (1) Relates to MGA trade receivables (included in other assets in the Company’s consolidated balance sheets), loans receivables (included in other long-term investments in the Company’s consolidated balance sheets) and interest and dividend receivables. The Company’s allowance for expected credit losses was $28.8 million as of March 31, 2024 (December 31, 2023 - $28.8 million). For the three months ended March 31, 2024, the Company did not record any change to the current expected credit losses (2023 - none). Changes to the current expected credit losses are included in net corporate and other expenses in the consolidated statements of income.

Debt and letter of credit facil

Debt and letter of credit facilities	3 Months Ended
	Mar. 31, 2024
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 consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Amount Effective rate (1) Amount Effective rate (1) 2017 SEK Subordinated Notes, at face value $ 257.8 8.2 % $ 273.6 7.7 % Unamortized discount (5.2) (5.7) 2017 SEK Subordinated Notes, carrying value 252.6 267.9 2016 Senior Notes, at face value 400.0 4.3 % 400.0 4.6 % Unamortized premium 3.2 3.5 2016 Senior Notes, carrying value 403.2 403.5 2015 Senior Notes, at face value 115.0 7.0 % 115.0 7.0 % Unamortized issuance costs (0.2) (0.2) 2015 Senior Notes, carrying value 114.8 114.8 Total debt $ 770.6 $ 786.2 (1) Effective rate considers the effect of the debt issuance costs, discount, and premium. The Company was in compliance with all debt covenants as of and for the periods ended March 31, 2024 and December 31, 2023. In April 2024, the Company issued $400.0 million aggregate principal amount of its 7.0% Senior Notes due 2029 (the “2024 Senior Notes”). Interest is payable on the 2024 Senior Notes semi-annually in arrears. The 2024 Senior Notes were issued pursuant to a Senior Indenture, dated as of April 5, 2024, between the Company and The Bank of New York Mellon, as trustee, and supplemented by a First Supplemental Indenture thereto with The Bank of New York Mellon, as trustee. The 2024 Senior Notes were offered and sold pursuant to the shelf registration statement on Form S-3 (File No. 333-255917), filed with the U.S. Securities and Exchange Commission (the “Commission”) on May 7, 2021, and a prospectus supplement related to the 2029 Notes dated March 27, 2024 (filed with the Commission pursuant to Rule 424(b)(2) under the Securities Act of 1933). In April 2024, the Company amended its 4.6% 2016 Senior Notes pursuant to a Fourth Supplemental Indenture thereto with The Bank of New York Mellon, as trustee, and following such amendments the Company completed the redemption of all remaining outstanding $400.0 million aggregate principal amount of its 2016 Senior Notes. The Company also redeemed all $115.0 million aggregate principal amount of its 2015 Senior Notes in April 2024. The Company has used certain of the proceeds from the 2024 Senior Notes, together with available cash, to fund the purchase of validly tendered 2016 Senior Notes and the redemptions of the 2016 Senior Notes and the 2015 Senior Notes. Standby letter of credit facilities As of March 31, 2024, the Company had entered into the following letter of credit facilities: March 31, 2024 Letters of Credit Collateral Committed Capacity Issued Cash and Cash Equivalents Debt securities Committed - Secured letters of credit facilities $ 355.0 $ 279.6 $ 16.4 $ 225.4 Uncommitted - Secured letters of credit facilities n/a 984.2 53.8 1,198.0 $ 1,263.8 $ 70.2 $ 1,423.4 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. Interest expense Total interest expense incurred by the Company for the three months ended March 31, 2024 includes $11.8 million (2023 - $12.8 million) associated with debt obligations, and funds withheld interest of $7.1 million (2023 - none) from the 2023 LPT. See Note 3 - Significant transactions for further discussion on the 2023 LPT. Revolving credit facility In addition to the letter of credit facilities above, 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, effective February 26, 2021, which was renewed in February 2024 for one ble, subject to customary conditions precedent. As of March 31, 2024, there were no outstanding borrowings under the Facility.

Income taxes

Income taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income taxes	14. Income taxes The Company provides income tax expense or benefit based upon pre-tax income or loss reported in the consolidated statements of income and the provisions of currently enacted tax laws. Under current Bermuda law, the Company and its Bermuda-domiciled subsidiaries are not subject to income taxes imposed by the government of Bermuda. Starting in 2025, a 15% corporate income tax is expected to apply to the Company’s Bermuda operations as a result of the enactment of the Corporate Income Tax Act 2023 (the “Bermuda CIT”). The Bermuda CIT legislation includes specific provisions intended to administer a fair and equitable transition into the new tax system, referred to as the economic transition adjustment (“ETA”) and opening tax loss carryforward (“OTLC”). The Company expects that SiriusPoint Ltd. and at least one of its major subsidiaries organized and operating in Bermuda will be subject to these provisions. The Company expects its in-scope entities will incur increased tax expense in Bermuda beginning in 2025. 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 Belgium, Bermuda, Canada, Germany, Gibraltar, Hong Kong (China), Luxembourg, Singapore, Sweden, Switzerland, the United Kingdom, and the United States. For the three months ended March 31, 2024, the Company recorded income tax expense of $9.7 million (2023 - $25.5 million) on pre-tax income of $105.6 million (2023 - $163.8 million). The effective tax rates for the three months ended March 31, 2024 was 9.2%. The difference between the effective tax rate on income (losses) from continuing operations and the Bermuda statutory tax rate of 0.0% is primarily because of income recognized in jurisdictions with higher tax rates than Bermuda, and adjustments pursuant to applicable U.S. GAAP guidance on interim period financial reporting of taxes, which are based on the annual estimated effective tax rate. In arriving at the estimated annual effective tax rate for the three months ended March 31, 2024 and 2023, 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. In December 2021, the OECD published two global anti-base erosion model rules under Pillar Two (the “GloBE Rules”), which implement a 15% global minimum tax applicable for multinational groups. The first GloBE Rule is the income inclusion rule (“IIR”), which imposes “top-up” tax on a parent entity in respect of the income of a subsidiary that is taxed at less than 15%. The second GloBE Rule is the “undertaxed payments” rule, which denies deductions or requires an equivalent adjustment to the extent the income of an affiliate which is taxed at less than 15%. On January 1, 2024, the GloBE Rules went into effect in the EU, including a minimum top-up tax rate of 15% for multinational companies, with many EU member states enacting corollary legislation as part of their respective domestic tax laws. The Company will continue to monitor how the relevant countries have enacted Pillar Two. Pillar Two is not expected to have a material impact to the current year financial statements. 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.

Shareholders' equity

Shareholders' equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Shareholders' equity	15. 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, 2024 and 2023: 2024 2023 Common shares issued and outstanding, beginning of period 168,120,022 162,177,653 Issuance of common shares, net of forfeitures and shares withheld 22,587 189,520 Issuance of common shares upon exercise of options 1,610,623 — Common shares issued and outstanding, end of period 169,753,232 162,367,173 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, 2024 and 2023, 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 The Series B preference shares are listed on the New York Stock Exchange under the symbol “SPNT PB”. The Company has 8,000,000 of Series B preference shares outstanding, par value $0.10. Dividends on the Series B preference shares are cumulative and payable quarterly in arrears at an initial rate of 8.0% per annum. The preference shareholders 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 five-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 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%. During the three months ended March 31, 2024, the Company declared and paid dividends of $4.0 million to the Series B preference shareholders (2023 - $4.0 million). The Company has declared and paid dividends to the Series B preference shareholders every quarter beginning June 30, 2021.

Earnings per share available to

Earnings per share available to SiriusPoint common shareholders	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings per share available to SiriusPoint common shareholders	16. Earnings per share available to SiriusPoint common shareholders The following sets forth the computation of basic and diluted earnings per share available to SiriusPoint common shareholders for the three months ended March 31, 2024 and 2023: 2024 2023 Weighted-average number of common shares outstanding: Basic number of common shares outstanding 168,934,114 160,905,860 Dilutive effect of options 1,030,515 138,464 Dilutive effect of warrants 1,605,246 — Dilutive effect of restricted share awards and units 2,811,088 3,086,622 Diluted number of common shares outstanding 174,380,963 164,130,946 Basic earnings per common share: Net income available to SiriusPoint common shareholders $ 90.8 $ 131.9 Net income allocated to SiriusPoint participating shareholders (6.1) (10.0) Net income allocated to SiriusPoint common shareholders $ 84.7 $ 121.9 Basic earnings per share available to SiriusPoint common shareholders $ 0.50 $ 0.76 Diluted earnings per common share: Net income available to SiriusPoint common shareholders $ 90.8 $ 131.9 Net income allocated to SiriusPoint participating shareholders (6.1) (10.0) Net income allocated to SiriusPoint common shareholders $ 84.7 $ 121.9 Diluted earnings per share available to SiriusPoint common shareholders $ 0.49 $ 0.74 For the three months ended March 31, 2024, no amounts were excluded from the computation of diluted earnings per share attributable to SiriusPoint common shareholders. For the three months ended March 31, 2023, options of 3,910,700, warrants of 32,516,293 and restricted share units of 48,900 were excluded from the computation of diluted earnings per share attributable to SiriusPoint common shareholders.

Related party transactions

Related party transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related party transactions	17. Related party transactions In addition to the transactions disclosed in Notes 7 and 10 to these 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 During the three months ended March 31, 2024, i nsurance and reinsurance contracts with certain of the Company’s insurance and MGA related parties resulted in gross premiums written of $17.0 million (2023 - $67.5 million). As of March 31, 2024, the Company had total receivables from these related parties of $56.3 million and no payables (December 31, 2023 - receivables of $61.8 million and no payables). Investments managed by related parties The following table provides the fair value of the Company's investments managed by related parties as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Third Point Enhanced LP $ 77.8 $ 77.5 Third Point Venture Offshore Fund I LP 24.7 25.0 Third Point Venture Offshore Fund II LP 3.1 3.1 Investments in related party investment funds, at fair value 105.6 105.6 Third Point Optimized Credit Portfolio (1) 587.2 562.0 Total investments managed by related parties $ 692.8 $ 667.6 (1) The Third Point Optimized Credit Portfolio is reported in debt securities available for sale and trading in the consolidated balance sheets Management, advisory and performance fees to related parties The total management, advisory and performance fees to related parties for the three months ended March 31, 2024 and 2023 were as follows: 2024 2023 Management and advisory fees $ 1.7 $ 1.7 Performance fees 0.4 — Total management, advisory and performance fees to related parties (1) $ 2.1 $ 1.7 (1) Management, advisory and performance fees for the Related Party Investment Funds, where applicable, are presented within net realized and unrealized investment gains from related party investment funds in the consolidated statements of income. Management and advisory fees Third Point Enhanced LP Pursuant to the 2022 LPA, effective February 23, 2022, 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% per annum of the investment in TP Enhanced Fund. Third Point Venture Offshore Fund I LP No management fees are payable by the Company under the 2021 Venture LPA . Third Point Venture Offshore Fund II LP Pursuant to the 2022 Venture II LPA, m anagement fees are charged at the TP Venture Fund II level and are calculated based on 0.1875% per quarter (0.75% per annum). Third Point Insurance Portfolio Solutions and Third Point Optimized Credit Pursuant to the Third Point Insurance Portfolio Solutions Investment Management Agreement (“TPIPS IMA”), effective February 26, 2021, 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 ). Pursuant to the 2022 IMA, effective February 23, 2022, the Company will also pay Third Point LLC a monthly management fee equal to one twelfth of 0.50% (0.50% per annum) of the TPOC Portfolio, net of any expenses, and a fixed advisory fee of $1.5 million per annum. Performance fees Third Point Enhanced LP Pursuant to the 2022 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 “Investments in related party investment fund, at fair value” on the Company’s consolidated balance sheets since the fees are charged at the TP Enhanced Fund level. 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 Venture Offshore Fund II LP Pursuant to the 2022 Venture II LPA, TP Venture GP II receives a performance fee allocation equal to 20% of the Company’s investment income in the related party investment fund. Third Point Optimized Credit Pursuant to the 2022 IMA, the Company will pay Third Point LLC, from the assets of each sub-account, an annual incentive fee equal to 15% of outperformance over a specified benchmark. The performance fee is included as part of “Net investment income” on the Company’s consolidated statements of income .

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	18. Commitments and contingencies Liability-classified capital instruments On February 26, 2021, the Company completed its acquisition of Sirius International Insurance Group, Ltd. (“Sirius Group”). The aggregate consideration for the transaction included the issuance of preference shares, warrants, and other contingent value components, which are recorded at fair value in the liability-classified capital instruments line of the consolidated balance sheets. Series A Preference Shares On February 26, 2021, certain holders of Sirius Group shares elected to receive Series A preference shares, par value $0.10 per share (“Series A Preference Shares”), with respect to the consideration price of the Sirius Group acquisition. The Company issued 11,720,987 Series A Preference Shares. 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. Upon the third anniversary of the closing date of the Sirius Group acquisition, the Series A Preference Shares were subject to a conversion ratio calculation, based on ultimate COVID-19 losses along with other measurement criteria, to convert into the Company’s common shares. The Company and Series A Preference Share investors are reviewing the COVID-19 loss estimates and the Company expects to settle the Series A Preference Shares upon the completion of the review process. During the three months ended March 31, 2024, the Company recorded a loss of $3.9 million, respectively, from the change in fair value of the Series A Preference Shares (2023 - $5.3 million). As of March 31, 2024, t he fair value of the Series A Preference Shares is $41.5 million ( December 31, 2023 - $37.6 million) . During the three months ended March 31, 2024, the Company did not declare or pay dividends to holders of Series A Preference Shares. Merger Warrants On February 26, 2021, the Company issued certain warrants with respect to the consideration price of the Sirius Group acquisition (the “Merger Warrants”) . As of March 31, 2024, 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. During the three months ended March 31, 2024, the Company recorded a loss of $12.0 million from the change in fair value of the Merger Warrants (2023 - $16.0 million). As of March 31, 2024, the estimated fair value of the Merger Warrants is $41.7 million (December 31, 2023 - $29.7 million). Sirius Group Private Warrants On February 26, 2021, the Company entered into an assumption agreement pursuant to which 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 certain counterparties. The 5,418,434 Private Warrants were all exercised before their maturity on November 5, 2023. During the three months ended March 31, 2023, the Company recorded a loss of $4.3 million from the change in fair value of the P rivate Warrants . Sirius Group Public Warrants Under the merger agreement between Sirius Group and Easterly Acquisition Corporation (“Easterly”), 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”). The Sirius Group Public Warrants expired without exercise on October 27, 2023. During the three months ended March 31, 2023, there was no change in the fair value of the Sirius Group Public Warrants. Contingent Value Rights On February 26, 2021, the Company entered into a contingent value rights agreement with respect to the consideration price of the Sirius Group acquisition. The contingent value rights (“ CVRs”) became publicly traded on the OTCQX Best Market during the quarter ended June 30, 2021. The CVRs matured on February 26, 2023 and were settled for $38.5 million. Promissory notes & loan agreement 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, 2024. On March 7, 2022, the Company entered into an Unsecured Convertible Promissory Note agreement with Player’s Health, pursuant to which the Company has lent $8.0 million. Interest shall accrue and be computed on the aggregate principal amount drawn and outstanding at a rate of 6.0% per annu m. Litigation From time to time in the normal course of business, the Company may be involved in formal and informal dispute resolution processes, which may include arbitration or litigation, the outcomes of which determine the rights and obligations under the Company’s reinsurance and insurance 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 processes that do not arise from, or are not directly related to, claims activity. The Company believes that no individual litigation or arbitration to which it is presently a party is likely to have a material adverse effect on its results of operations, financial condition, business or operations. Leases The Company operates in Bermuda, the United States, Canada, Europe and Asia, and leases office space under various non-cancelable operating lease agreements. During the three months ended March 31, 2024, the Company recognized operating lease expense of $2.2 million, respectively (2023 - $2.5 million), including property taxes and routine maintenance expense as well as rental expenses related to short term leases. The following table presents the lease balances within the consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, December 31, Operating lease right-of-use assets (1) $ 24.2 $ 25.6 Operating lease liabilities (2) $ 26.6 $ 28.4 Weighted average lease term (years) 3.9 4.1 Weighted average discount rate 2.9 % 2.9 % (1) Operating lease right-of-use assets are included in other assets . (2) Operating lease liabilities are included in accounts payable, accrued expenses and other liabilities on the Company’s consolidated balance sheets . Future minimum rental commitments as of March 31, 2024 under these leases are expected to be as follows: Future Payments Remainder of 2024 $ 4.9 2025 5.8 2026 5.0 2027 4.1 2028 and thereafter 9.2 Total future annual minimum rental payments 29.0 Less: present value discount (2.4) Total lease liability as of March 31, 2024 $ 26.6

Subsequent event

Subsequent event	3 Months Ended
	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent event	19. Subsequent event Loss portfolio transfer On April 30, 2024, SiriusPoint America Insurance Company (“SiriusPoint America”), a subsidiary of SiriusPoint Ltd., entered into a Master Agreement (the “Master Agreement”), dated as of April 30, 2024, made by and between SiriusPoint America and Clarendon National Insurance Company (“Clarendon National”), an insurer domiciled in Texas and an affiliate of Enstar Group Limited, a Bermuda exempted company (“Enstar”). Pursuant to the Master Agreement, at the closing of the transactions contemplated therein, among other documents, (a) SiriusPoint America and Clarendon National will enter into a Loss Portfolio Transfer Reinsurance Agreement (the “LPT Agreement”), pursuant to which SiriusPoint America will cede and Clarendon National will assume 100% of the net liability with respect to certain workers’ compensation insurance exposures of SiriusPoint America (the “Subject Business”) on a funds withheld basis, subject to the terms and conditions of the LPT Agreement including an aggregate limit; (b) SiriusPoint America and an affiliate of Clarendon National (the “Administrator”) will enter into an Administrative Services Agreement concerning the Administrator’s authority and responsibility for certain administrative services related to the Subject Business, including claims handling; and (c) Enstar shall issue a Parental Guarantee in favor of SiriusPoint America guaranteeing Clarendon National’s obligations under the LPT Agreement. In certain circumstances and in lieu of the guarantee obligations provided thereunder, Clarendon National may post letters of credit as collateral securing Clarendon National’s reinsurance obligations with respect to the Subject Business. Immediately prior to the effective date of the LPT Agreement, SiriusPoint will be commuting certain ceded workers’ compensation reinsurance contracts, and the liabilities related to those commuted contracts will be included in the Subject Business. This transaction covers approximately $400 million of SiriusPoint reserves, including liabilities to be commuted, valued as of December 31, 2023, and the reinsurance premium. The aggregate limit under the LPT Agreements is 150% of the premium paid less certain adjustments for paid losses in the interim period prior to the effective date of the contract. The Master Agreement and the LPT Agreements include customary representations and warranties, indemnification obligations, covenants and termination rights of the parties. The transaction is anticipated to close and incept on or around June 30, 2024, subject to regulatory approvals and other customary closing conditions.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 94.8	$ 135.9

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Significant accounting polici_2

Significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Recently issued accounting standards	Recently issued accounting standards Issued and effective as of March 31, 2024 In June 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions (“ASU 2022-03”). The amendment clarifies the guidance in Topic 820 on the fair value measurement of an equity security that is subject to a contractual sale restriction and requires specific disclosures related to such an equity security. ASU 2022-03 is effective for public business entities for fiscal years beginning after December 15, 2023 and interim periods within those fiscal years. This pronouncement did not have a material impact on the Company’s consolidated financial statements. Issued but not yet effective as of March 31, 2024 Accounting pronouncements issued during the three months ended March 31, 2024 were either not relevant to the Company or did not impact the Company’s consolidated financial statements.

Segment reporting (Tables)

Segment reporting (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and 2023: Three months ended March 31, 2024 Reinsurance Insurance & Services Core Eliminations (2) Corporate Segment Measure Reclass Total Gross premiums written $ 356.4 $ 524.3 $ 880.7 $ — $ 25.9 $ — $ 906.6 Net premiums written 290.1 337.1 627.2 — 12.1 — 639.3 Net premiums earned 253.6 264.2 517.8 — 76.0 — 593.8 Loss and loss adjustment expenses incurred, net 124.6 176.5 301.1 (1.4) 17.8 — 317.5 Acquisition costs, net 69.8 65.2 135.0 (33.2) 43.1 — 144.9 Other underwriting expenses 19.3 18.1 37.4 — 4.4 — 41.8 Underwriting income 39.9 4.4 44.3 34.6 10.7 — 89.6 Services revenues — 65.8 65.8 (37.1) — (28.7) — Services expenses — 46.0 46.0 — — (46.0) — Net services fee income — 19.8 19.8 (37.1) — 17.3 — Services noncontrolling income — (1.7) (1.7) — — 1.7 — Net services income — 18.1 18.1 (37.1) — 19.0 — Segment income 39.9 22.5 62.4 (2.5) 10.7 19.0 89.6 Net investment income 78.8 — 78.8 Net realized and unrealized investment gains 1.0 — 1.0 Other revenues (16.8) 28.7 11.9 Net corporate and other expenses (10.0) (46.0) (56.0) Intangible asset amortization (2.9) — (2.9) Interest expense (20.5) — (20.5) Foreign exchange gains 3.7 — 3.7 Income before income tax expense $ 39.9 $ 22.5 62.4 (2.5) 44.0 1.7 105.6 Income tax expense — — (9.7) — (9.7) Net income 62.4 (2.5) 34.3 1.7 95.9 Net (income) loss attributable to noncontrolling interests — — 0.6 (1.7) (1.1) Net income available to SiriusPoint $ 62.4 $ (2.5) $ 34.9 $ — $ 94.8 Underwriting Ratios: (1) Loss ratio 49.1 % 66.8 % 58.1 % 53.5 % Acquisition cost ratio 27.5 % 24.7 % 26.1 % 24.4 % Other underwriting expenses ratio 7.6 % 6.9 % 7.2 % 7.0 % Combined ratio 84.2 % 98.4 % 91.4 % 84.9 % (1) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (2) Insurance & Services MGAs recognize fees for service using revenue from contracts with customers accounting standards, whereas insurance companies recognize acquisition expenses using insurance contract accounting standards. While ultimate revenues and expenses recognized will match, there will be recognition timing differences based on the different accounting standards. Three months ended March 31, 2023 Reinsurance Insurance & Services Core Eliminations (2) Corporate Segment Measure Reclass Total Gross premiums written $ 396.2 $ 664.0 $ 1,060.2 $ — $ 50.3 $ — $ 1,110.5 Net premiums written 311.0 452.6 763.6 — 28.1 — 791.7 Net premiums earned 259.5 291.2 550.7 — 44.8 — 595.5 Loss and loss adjustment expenses incurred, net 85.6 172.5 258.1 (1.3) 10.3 — 267.1 Acquisition costs, net 66.0 71.7 137.7 (32.5) 14.5 — 119.7 Other underwriting expenses 28.2 19.3 47.5 — 4.7 — 52.2 Underwriting income 79.7 27.7 107.4 33.8 15.3 — 156.5 Services revenues 0.2 63.6 63.8 (34.3) — (29.5) — Services expenses — 45.5 45.5 — — (45.5) — Net services fee income 0.2 18.1 18.3 (34.3) — 16.0 — Services noncontrolling income — (1.6) (1.6) — — 1.6 — Net services income 0.2 16.5 16.7 (34.3) — 17.6 — Segment income 79.9 44.2 124.1 (0.5) 15.3 17.6 156.5 Net investment income 61.7 — 61.7 Net realized and unrealized investment gains 11.3 — 11.3 Net realized and unrealized investment gains from related party investment funds 0.8 — 0.8 Other revenues (20.7) 29.5 8.8 Net corporate and other expenses (14.5) (45.5) (60.0) Intangible asset amortization (2.4) — (2.4) Interest expense (12.8) — (12.8) Foreign exchange losses (0.1) — (0.1) Income before income tax expense $ 79.9 $ 44.2 124.1 (0.5) 38.6 1.6 163.8 Income tax expense — — (25.5) — (25.5) Net income 124.1 (0.5) 13.1 1.6 138.3 Net income attributable to noncontrolling interests — — (0.8) (1.6) (2.4) Net income available to SiriusPoint $ 124.1 $ (0.5) $ 12.3 $ — $ 135.9 Underwriting Ratios: (1) Loss ratio 33.0 % 59.2 % 46.9 % 44.9 % Acquisition cost ratio 25.4 % 24.6 % 25.0 % 20.1 % Other underwriting expenses ratio 10.9 % 6.6 % 8.6 % 8.8 % Combined ratio 69.3 % 90.4 % 80.5 % 73.8 % (1) Underwriting ratios are calculated by dividing the related expense by net premiums earned. (2) Insurance & Services MGAs recognize fees for service using revenue from contracts with customers accounting standards, whereas insurance companies recognize acquisition expenses using insurance contract accounting standards. While ultimate revenues and expenses recognized will match, there will be recognition timing differences based on the different accounting standards.

Cash, cash equivalents, restr_2

Cash, cash equivalents, restricted cash and restricted investments (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and December 31, 2023: March 31, December 31, Cash and cash equivalents $ 867.5 $ 969.2 Restricted cash securing letter of credit facilities (1) 70.2 56.9 Restricted cash securing reinsurance contracts (2) 119.6 52.7 Restricted cash held by managing general underwriters 29.1 22.5 Total cash, cash equivalents and restricted cash (3) 1,086.4 1,101.3 Restricted investments securing reinsurance contracts and letter of credit facilities (1) (2) (4) 2,658.5 2,668.0 Total cash, cash equivalents, restricted cash and restricted investments $ 3,744.9 $ 3,769.3 (1) Restricted cash and restricted investments 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, short-term investments 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 consolidated statements of cash flows. (4) Restricted investments include required deposits with certain insurance state regulatory agencies in order to maintain insurance licenses.
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, 2024 and December 31, 2023: March 31, December 31, Cash and cash equivalents $ 867.5 $ 969.2 Restricted cash securing letter of credit facilities (1) 70.2 56.9 Restricted cash securing reinsurance contracts (2) 119.6 52.7 Restricted cash held by managing general underwriters 29.1 22.5 Total cash, cash equivalents and restricted cash (3) 1,086.4 1,101.3 Restricted investments securing reinsurance contracts and letter of credit facilities (1) (2) (4) 2,658.5 2,668.0 Total cash, cash equivalents, restricted cash and restricted investments $ 3,744.9 $ 3,769.3 (1) Restricted cash and restricted investments 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, short-term investments 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 consolidated statements of cash flows. (4) Restricted investments include required deposits with certain insurance state regulatory agencies in order to maintain insurance licenses.

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and December 31, 2023: March 31, 2024 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 1,044.0 $ — $ 1,044.0 Residential mortgage-backed securities — 926.8 — 926.8 Commercial mortgage-backed securities — 236.5 — 236.5 Corporate debt securities — 1,730.8 — 1,730.8 U.S. government and government agency 1,066.6 2.9 — 1,069.5 Non-U.S. government and government agency — 49.9 — 49.9 Total debt securities, available for sale 1,066.6 3,990.9 — 5,057.5 Asset-backed securities — 199.7 — 199.7 Residential mortgage-backed securities — 55.3 — 55.3 Commercial mortgage-backed securities — 66.2 — 66.2 Corporate debt securities — 41.5 — 41.5 U.S. government and government agency 33.4 — — 33.4 Non-U.S. government and government agency — 9.9 — 9.9 Total debt securities, trading 33.4 372.6 — 406.0 Total equity securities 1.6 — — 1.6 Short-term investments 295.2 34.7 — 329.9 Other long-term investments — — 170.6 170.6 Derivative assets — — 1.4 1.4 $ 1,396.8 $ 4,398.2 $ 172.0 5,967.0 Cost and equity method investments 73.6 Investments in funds valued at NAV 158.0 Total assets $ 6,198.6 Liabilities Liability-classified capital instruments $ — $ — $ 83.2 $ 83.2 Derivative liabilities — — 20.6 20.6 Total liabilities $ — $ — $ 103.8 $ 103.8 December 31, 2023 Quoted prices in active markets Significant other observable inputs Significant unobservable inputs Total (Level 1) (Level 2) (Level 3) Assets Asset-backed securities $ — $ 880.7 $ — $ 880.7 Residential mortgage-backed securities — 902.8 — 902.8 Commercial mortgage-backed securities — 204.1 — 204.1 Corporate debt securities — 1,573.1 — 1,573.1 U.S. government and government agency 1,132.6 4.1 — 1,136.7 Non-U.S. government and government agency — 58.0 — 58.0 Total debt securities, available for sale 1,132.6 3,622.8 — 4,755.4 Asset-backed securities — 256.6 — 256.6 Residential mortgage-backed securities — 57.2 — 57.2 Commercial mortgage-backed securities — 67.8 — 67.8 Corporate debt securities — 45.2 — 45.2 U.S. Government and government agency 98.1 — — 98.1 Non-U.S. government and government agency — 10.0 — 10.0 Total debt securities, trading 98.1 436.8 — 534.9 Total equity securities 1.6 — — 1.6 Short-term investments 321.9 49.7 — 371.6 Other long-term investments — — 169.7 169.7 Derivative assets — — 15.7 15.7 $ 1,554.2 $ 4,109.3 $ 185.4 5,848.9 Cost and equity method investments 80.1 Investments in funds valued at NAV 164.3 Total assets $ 6,093.3 Liabilities Securities sold under an agreement to repurchase $ — $ — $ 67.3 $ 67.3 Derivative liabilities — — 6.4 6.4 Total liabilities $ — $ — $ 73.7 $ 73.7
Reconciliation of assets measured at fair value using Level 3 inputs	The following tables present the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2024 and 2023: January 1, 2024 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2024 Assets Other long-term investments $ 169.7 $ — $ — $ — $ 0.9 $ 170.6 Derivative assets 15.7 — — (4.6) (9.7) 1.4 Total assets $ 185.4 $ — $ — $ (4.6) $ (8.8) $ 172.0 Liabilities Liability-classified capital instruments $ (67.3) $ — $ — $ — $ (15.9) $ (83.2) Derivative liabilities (6.4) — — (1.1) (13.1) (20.6) Total liabilities $ (73.7) $ — $ — $ (1.1) $ (29.0) $ (103.8) January 1, 2023 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2023 Assets Preferred stocks $ 3.2 $ — $ — $ — $ — $ 3.2 Other long-term investments 227.3 — 0.4 — (0.3) 227.4 Derivative assets 9.5 — 2.5 (2.1) 1.4 11.3 Total assets $ 240.0 $ — $ 2.9 $ (2.1) $ 1.1 $ 241.9 Liabilities Liability-classified capital instruments $ (21.4) $ — $ — $ — $ (25.6) $ (47.0) Derivative liabilities (8.6) — (3.2) 1.5 1.9 (8.4) Total liabilities $ (30.0) $ — $ (3.2) $ 1.5 $ (23.7) $ (55.4) (1) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in total net investment income and realized and unrealized investment gains in the consolidated statements of income. 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 consolidated statements of income.
Reconciliation of liabilities measured at fair value using Level 3 inputs	The following tables present the reconciliation of all investments measured at fair value using Level 3 inputs for the three months ended March 31, 2024 and 2023: January 1, 2024 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2024 Assets Other long-term investments $ 169.7 $ — $ — $ — $ 0.9 $ 170.6 Derivative assets 15.7 — — (4.6) (9.7) 1.4 Total assets $ 185.4 $ — $ — $ (4.6) $ (8.8) $ 172.0 Liabilities Liability-classified capital instruments $ (67.3) $ — $ — $ — $ (15.9) $ (83.2) Derivative liabilities (6.4) — — (1.1) (13.1) (20.6) Total liabilities $ (73.7) $ — $ — $ (1.1) $ (29.0) $ (103.8) January 1, 2023 Transfers in to (out of) Level 3 Purchases Sales & Settlements Realized and Unrealized Gains (Losses) (1) March 31, 2023 Assets Preferred stocks $ 3.2 $ — $ — $ — $ — $ 3.2 Other long-term investments 227.3 — 0.4 — (0.3) 227.4 Derivative assets 9.5 — 2.5 (2.1) 1.4 11.3 Total assets $ 240.0 $ — $ 2.9 $ (2.1) $ 1.1 $ 241.9 Liabilities Liability-classified capital instruments $ (21.4) $ — $ — $ — $ (25.6) $ (47.0) Derivative liabilities (8.6) — (3.2) 1.5 1.9 (8.4) Total liabilities $ (30.0) $ — $ (3.2) $ 1.5 $ (23.7) $ (55.4) (1) Total change in realized and unrealized gains (losses) recorded on Level 3 financial instruments is included in total net investment income and realized and unrealized investment gains in the consolidated statements of income. 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 consolidated statements of income.
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, 2024 and December 31, 2023. The fair values of the below financial instruments are based on observable inputs and are considered Level 2 measurements. March 31, 2024 December 31, 2023 Fair Value Carrying Value Fair Value Carrying Value 2017 SEK Subordinated Notes $ 214.0 $ 252.6 $ 206.6 $ 267.9 2016 Senior Notes 382.0 403.2 370.0 403.5 2015 Senior Notes 113.9 114.8 115.2 114.8 Series B preference shares $ 202.6 $ 200.0 $ 197.4 $ 200.0

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2024
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 March 31, 2024 Cost or Gross Gross Net foreign Fair value Debt securities, available for sale Asset-backed securities $ 1,040.7 $ 9.5 $ (6.2) $ — $ 1,044.0 Residential mortgage-backed securities 930.9 12.9 (17.0) — 926.8 Commercial mortgage-backed securities 236.9 1.4 (1.8) — 236.5 Corporate debt securities 1,739.4 5.9 (14.1) (0.4) 1,730.8 U.S. government and government agency 1,077.0 1.7 (9.2) — 1,069.5 Non-U.S. government and government agency 50.5 — (0.4) (0.2) 49.9 Total debt securities, available for sale (1) $ 5,075.4 $ 31.4 $ (48.7) $ (0.6) $ 5,057.5 Debt securities, trading Asset-backed securities $ 203.0 $ 0.6 $ (3.9) $ — $ 199.7 Residential mortgage-backed securities 64.1 — (8.8) — 55.3 Commercial mortgage-backed securities 73.2 0.1 (7.1) — 66.2 Corporate debt securities 48.7 — (7.2) — 41.5 U.S. government and government agency 34.1 — (0.7) — 33.4 Non-U.S. government and government agency 10.2 — (0.3) — 9.9 Total debt securities, trading $ 433.3 $ 0.7 $ (28.0) $ — $ 406.0 December 31, 2023 Cost or Gross Gross Net foreign Fair value Debt securities, available for sale Asset-backed securities $ 882.2 $ 7.8 $ (9.3) $ — $ 880.7 Residential mortgage-backed securities 903.0 15.8 (16.0) — 902.8 Commercial mortgage-backed securities 204.0 1.6 (1.5) — 204.1 Corporate debt securities 1,569.6 12.0 (7.5) (1.0) 1,573.1 U.S. government and government agency 1,137.8 5.5 (6.6) — 1,136.7 Non-U.S. government and government agency 58.0 0.2 (0.3) 0.1 58.0 Total debt securities, available for sale (1) $ 4,754.6 $ 42.9 $ (41.2) $ (0.9) $ 4,755.4 Debt securities, trading Asset-backed securities $ 261.1 $ 0.6 $ (5.1) $ — $ 256.6 Residential mortgage-backed securities 67.0 — (9.8) — 57.2 Commercial mortgage-backed securities 76.7 0.1 (9.0) — 67.8 Corporate debt securities 52.2 — (7.0) — 45.2 U.S. government and government agency 100.8 — (2.7) — 98.1 Non-U.S. government and government agency 10.3 — (0.3) — 10.0 Total debt securities, trading $ 568.1 $ 0.7 $ (33.9) $ — $ 534.9 (1)
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 bifurcated into debt securities held for trading and AFS as of March 31, 2024 and December 31, 2023 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, 2024 December 31, 2023 Debt securities, AFS Debt securities, trading Debt securities, AFS Debt securities, trading Cost or Fair value Cost or Fair value Cost or Fair value Cost or Fair value Due in one year or less $ 460.3 $ 457.7 $ 14.2 $ 14.0 $ 358.6 $ 357.2 $ 80.2 $ 79.7 Due after one year through five years 2,131.5 2,116.0 32.9 32.2 2,221.0 2,219.8 37.2 34.5 Due after five years through ten years 272.4 274.2 19.4 17.9 183.3 188.5 19.4 18.0 Due after ten years 2.7 2.3 26.5 20.8 2.5 2.3 26.6 21.3 Mortgage-backed and asset-backed securities 2,208.5 2,207.3 340.3 321.1 1,989.2 1,987.6 404.7 381.4 Total debt securities $ 5,075.4 $ 5,057.5 $ 433.3 $ 406.0 $ 4,754.6 $ 4,755.4 $ 568.1 $ 534.9
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, 2024 and December 31, 2023. Credit ratings are assigned based on ratings provided by nationally recognized statistical rating organizations. March 31, 2024 December 31, 2023 Debt securities, AFS Debt securities, trading Debt securities, AFS Debt securities, trading AAA $ 796.6 $ 197.4 $ 730.4 $ 248.4 AA 2,378.8 110.1 2,334.4 177.0 A 1,312.2 19.3 1,122.1 28.9 BBB 485.5 70.9 515.5 71.7 Other 84.4 8.3 53.0 8.9 Total debt securities $ 5,057.5 $ 406.0 $ 4,755.4 $ 534.9
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, 2024 and December 31, 2023 were as follows: Cost or Gross Gross Net foreign Fair value March 31, 2024 Equity securities $ 1.6 $ — $ (0.2) $ 0.2 $ 1.6 Other long-term investments $ 343.1 $ 20.7 $ (70.3) $ 3.1 $ 296.6 December 31, 2023 Equity securities $ 1.9 $ — $ (0.5) $ 0.2 $ 1.6 Other long-term investments $ 356.2 $ 20.0 $ (70.1) $ 2.4 $ 308.5 The Company holds investments in hedge funds and private equity funds, which are included in other long-term investments. The carrying value of other long-term investments as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Hedge funds and private equity funds (1) $ 70.1 $ 74.5 Strategic investments (2) 196.4 203.9 Other investments (2) 30.1 30.1 Total other long-term investments $ 296.6 $ 308.5 (1) Incl udes $52.2 million of investments carried at NAV (December 31, 2023 - $58.7 million) and no investments classified as Level 3 (December 31, 2023 - no investments classified as Level 3) within the fair value hierarchy. (2) As of March 31, 2024, the Company had $12.1 million of unfunded commitments relating to these investments ( December 31, 2023 - $14.7 million).
Schedule of other long-term investments	The following table presents the components of other long-term investments as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Equity method eligible unconsolidated entities, using the fair value option $ 139.0 $ 139.2 Equity method investments 40.9 37.0 Other unconsolidated investments, at fair value (1) 84.0 89.2 Other unconsolidated investments, at cost (2) 32.7 43.1 Total other long-term investments $ 296.6 $ 308.5 (1) Includes other long-term investments that are not equity method eligible and are measured at fair value. (2) The Company has elected to apply the cost adjusted for market observable events impairment measurement alternative to investments that do not meet the criteria to be accounted for under the equity method, in which the investment is measured at cost and remeasured to fair value when impaired or upon observable transaction prices.
Schedule of investments in related party investment funds	The following table provides the fair value of the Company's investments in related party investment funds as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Third Point Enhanced LP $ 77.8 $ 77.5 Third Point Venture Offshore Fund I LP 24.7 25.0 Third Point Venture Offshore Fund II LP 3.1 3.1 Investments in related party investment funds, at fair value $ 105.6 $ 105.6

Total net investment income a_2

Total net investment income and realized and unrealized investment gains (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of net investment income and total realized and unrealized investment gains (losses)	Net investment income and net realized and unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, available for sale $ 63.7 $ 35.1 Debt securities, trading 8.8 29.1 Short-term investments 4.4 8.4 Other long-term investments 0.5 4.4 Derivative instruments 1.3 — Net realized and unrealized investment gains from related party investment funds — 0.8 Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents 78.7 77.8 Investment expenses (3.9) (5.4) Net investment income on cash and cash equivalents 5.0 1.4 Total net investment income and realized and unrealized gains on investments $ 79.8 $ 73.8
Schedule of net realized investment gains (losses)	Net realized and unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Gross realized gains $ 5.5 $ 5.8 Gross realized losses (9.2) (15.6) Net realized losses on investments (3.7) (9.8) Net unrealized gains on investments 4.7 21.1 Net realized and unrealized gains on investments (1)(2) $ 1.0 $ 11.3 (1) Excludes realized and unrealized gains on the Company’s investments in related party investment funds and unrealized gains (losses) from available for sale investments, net of tax. (2) Includes net realized and unrealized gains (losses) of $(1.9) million from related party investments included in other-long term investments for the three months ended March 31, 2024 (2023 - $1.8 million). Net realized investment losses for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, available for sale $ (0.3) $ (0.6) Debt securities, trading (3.4) (7.4) Short-term investments 0.6 (0.2) Other long-term investments (0.8) (0.4) Net investment income (loss) on cash and cash equivalents 0.2 (1.2) Net realized investment losses $ (3.7) $ (9.8) Net realized investment losses on Other long-term investments for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Hedge funds and private equity funds $ 1.0 $ (0.4) Strategic investments (1.8) — Net realized investment losses on Other long-term investments $ (0.8) $ (0.4)
Schedule of net unrealized investment gains (losses)	Net realized and unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Gross realized gains $ 5.5 $ 5.8 Gross realized losses (9.2) (15.6) Net realized losses on investments (3.7) (9.8) Net unrealized gains on investments 4.7 21.1 Net realized and unrealized gains on investments (1)(2) $ 1.0 $ 11.3 (1) Excludes realized and unrealized gains on the Company’s investments in related party investment funds and unrealized gains (losses) from available for sale investments, net of tax. (2) Includes net realized and unrealized gains (losses) of $(1.9) million from related party investments included in other-long term investments for the three months ended March 31, 2024 (2023 - $1.8 million). Net unrealized investment gains for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Debt securities, trading $ 5.4 $ 23.0 Short-term investments (0.9) (0.4) Derivative instruments 1.0 — Other long-term investments 1.3 (3.0) Net investment income (loss) on cash and cash equivalents (2.1) 1.5 Net unrealized investment gains $ 4.7 $ 21.1 Net unrealized investment gains (losses) on Other long-term investments for the three months ended March 31, 2024 and 2023 consisted of the following: 2024 2023 Hedge funds and private equity funds $ (0.6) $ 0.9 Strategic investments 1.9 (3.9) Net unrealized investment gains (losses) on Other long-term investments $ 1.3 $ (3.0) The following table summarizes the amount of total gains (losses) included in earnings attributable to unrealized investment gains (losses) – Level 3 investments for the three months ended March 31, 2024 and 2023: 2024 2023 Debt securities, trading $ — $ 0.1 Other long-term investments 1.1 (4.8) Total unrealized investment gains (losses) – Level 3 investments $ 1.1 $ (4.7)

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2024
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 consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Derivatives not designated as hedging instruments Derivative assets at fair value (1) Derivative liabilities at fair value (2) Notional Derivative assets at fair value (1) Derivative liabilities at fair value (2) Notional Foreign currency forwards $ 1.1 $ 6.9 $ 808.6 $ 12.0 $ — $ 585.3 Weather derivatives 0.1 5.1 20.4 0.2 1.0 30.6 Interest rate swaps 0.1 — 62.7 3.4 1.7 62.7 Credit default swap 0.1 — 30.0 0.1 — 30.0 Reinsurance contracts accounted for as derivatives $ — $ 8.6 $ 94.3 $ — $ 3.7 $ 97.4 (1) Derivative assets are classified within other assets in the Company’s consolidated balance sheets . (2) Derivative liabilities are classified within accounts payable, accrued expenses and other liabilities in the Company’s consolidated balance sheets.
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 consolidated statements of income relating to derivatives during the three months ended March 31, 2024 and 2023: Derivatives not designated as hedging instruments Classification of gains (losses) recognized in earnings 2024 2023 Foreign currency forwards Foreign exchange (gains) losses $ (17.4) $ (1.6) Weather derivatives Other revenues (1.5) 3.5 Foreign currency swaps Foreign exchange (gains) losses — (1.6) Interest rate swaps Net realized and unrealized investment gains 1.3 — Reinsurance contracts accounted for as derivatives Other revenues $ (4.8) $ 0.1

Variable and voting interest _2

Variable and voting interest entities (Tables)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of noncontrolling interests	The following table is a reconciliation of the beginning and ending carrying amount of noncontrolling interests for the three months ended March 31, 2024 and 2023: 2024 2023 Balance, beginning of period $ 16.7 $ 7.9 Net income attributable to noncontrolling interests 1.1 2.4 Contributions — 1.1 Balance, end of period $ 17.8 $ 11.4
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, 2024 and December 31, 2023: Maximum Exposure to Loss Total VIE Assets On-Balance Sheet Off-Balance Sheet Total March 31, 2024 Other long-term investments (1) $ 175.8 $ 126.2 $ 1.9 $ 128.1 December 31, 2023 Other long-term investments (1) $ 189.8 $ 126.2 $ 5.7 $ 131.9 (1)

Loss and loss adjustment expe_2

Loss and loss adjustment expense reserves (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and 2023: 2024 2023 Gross reserves for loss and loss adjustment expenses, beginning of period $ 5,608.1 $ 5,268.7 Less: loss and loss adjustment expenses recoverable, beginning of period (2,295.1) (1,376.2) Less: deferred charges on retroactive reinsurance contracts 27.5 (1.0) Net reserves for loss and loss adjustment expenses, beginning of period 3,340.5 3,891.5 Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in: Current year 356.4 372.5 Prior years (38.9) (105.4) Total incurred loss and loss adjustment expenses 317.5 267.1 Net loss and loss adjustment expenses paid in respect of losses occurring in: Current year (44.0) (36.4) Prior years (272.8) (202.1) Total net paid losses (316.8) (238.5) Foreign currency translation 15.8 6.0 Net reserves for loss and loss adjustment expenses, end of period 3,357.0 3,926.1 Plus: loss and loss adjustment expenses recoverable, end of period 2,233.8 1,392.0 Plus: deferred (gains) charges on retroactive reinsurance (1) (25.5) 0.8 Gross reserves for loss and loss adjustment expenses, end of period $ 5,565.3 $ 5,318.9 (1) Deferred charges on retroactive reinsurance are recorded in other assets on the Company’s consolidated balance sheets. Deferred gains on retroactive reinsurance are presented as a separate line item on the Company’s consolidated balance sheets.

Allowance for expected credit_2

Allowance for expected credit losses (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and December 31, 2023 are as follows: March 31, 2024 December 31, 2023 Insurance and reinsurance balances receivable, net $ 2,127.2 $ 1,966.3 Loss and loss adjustment expenses recoverable, net 2,233.8 2,295.1 Other assets (1) 84.6 76.8 Total assets in scope $ 4,445.6 $ 4,338.2 (1)

Debt and letter of credit fac_2

Debt and letter of credit facilities (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of debt obligations	The following table represents a summar y of the Company’s debt obl igations on its consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Amount Effective rate (1) Amount Effective rate (1) 2017 SEK Subordinated Notes, at face value $ 257.8 8.2 % $ 273.6 7.7 % Unamortized discount (5.2) (5.7) 2017 SEK Subordinated Notes, carrying value 252.6 267.9 2016 Senior Notes, at face value 400.0 4.3 % 400.0 4.6 % Unamortized premium 3.2 3.5 2016 Senior Notes, carrying value 403.2 403.5 2015 Senior Notes, at face value 115.0 7.0 % 115.0 7.0 % Unamortized issuance costs (0.2) (0.2) 2015 Senior Notes, carrying value 114.8 114.8 Total debt $ 770.6 $ 786.2 (1) Effective rate considers the effect of the debt issuance costs, discount, and premium.
Schedule of letter of credit facilities	As of March 31, 2024, the Company had entered into the following letter of credit facilities: March 31, 2024 Letters of Credit Collateral Committed Capacity Issued Cash and Cash Equivalents Debt securities Committed - Secured letters of credit facilities $ 355.0 $ 279.6 $ 16.4 $ 225.4 Uncommitted - Secured letters of credit facilities n/a 984.2 53.8 1,198.0 $ 1,263.8 $ 70.2 $ 1,423.4

Shareholders' equity (Tables)

Shareholders' equity (Tables)	3 Months Ended
	Mar. 31, 2024
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, 2024 and 2023: 2024 2023 Common shares issued and outstanding, beginning of period 168,120,022 162,177,653 Issuance of common shares, net of forfeitures and shares withheld 22,587 189,520 Issuance of common shares upon exercise of options 1,610,623 — Common shares issued and outstanding, end of period 169,753,232 162,367,173

Earnings per share available _2

Earnings per share available to SiriusPoint common shareholders (Tables)	3 Months Ended
	Mar. 31, 2024
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 per share available to SiriusPoint common shareholders for the three months ended March 31, 2024 and 2023: 2024 2023 Weighted-average number of common shares outstanding: Basic number of common shares outstanding 168,934,114 160,905,860 Dilutive effect of options 1,030,515 138,464 Dilutive effect of warrants 1,605,246 — Dilutive effect of restricted share awards and units 2,811,088 3,086,622 Diluted number of common shares outstanding 174,380,963 164,130,946 Basic earnings per common share: Net income available to SiriusPoint common shareholders $ 90.8 $ 131.9 Net income allocated to SiriusPoint participating shareholders (6.1) (10.0) Net income allocated to SiriusPoint common shareholders $ 84.7 $ 121.9 Basic earnings per share available to SiriusPoint common shareholders $ 0.50 $ 0.76 Diluted earnings per common share: Net income available to SiriusPoint common shareholders $ 90.8 $ 131.9 Net income allocated to SiriusPoint participating shareholders (6.1) (10.0) Net income allocated to SiriusPoint common shareholders $ 84.7 $ 121.9 Diluted earnings per share available to SiriusPoint common shareholders $ 0.49 $ 0.74

Related party transactions (Tab

Related party transactions (Tables)	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Schedule of related party transactions	The following table provides the fair value of the Company's investments managed by related parties as of March 31, 2024 and December 31, 2023: March 31, 2024 December 31, 2023 Third Point Enhanced LP $ 77.8 $ 77.5 Third Point Venture Offshore Fund I LP 24.7 25.0 Third Point Venture Offshore Fund II LP 3.1 3.1 Investments in related party investment funds, at fair value 105.6 105.6 Third Point Optimized Credit Portfolio (1) 587.2 562.0 Total investments managed by related parties $ 692.8 $ 667.6 (1) The Third Point Optimized Credit Portfolio is reported in debt securities available for sale and trading in the consolidated balance sheets The total management, advisory and performance fees to related parties for the three months ended March 31, 2024 and 2023 were as follows: 2024 2023 Management and advisory fees $ 1.7 $ 1.7 Performance fees 0.4 — Total management, advisory and performance fees to related parties (1) $ 2.1 $ 1.7 (1) Management, advisory and performance fees for the Related Party Investment Funds, where applicable, are presented within net realized and unrealized investment gains from related party investment funds in the consolidated statements of income.

Commitment and contingencies (T

Commitment and contingencies (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of lease balances	The following table presents the lease balances within the consolidated balance sheets as of March 31, 2024 and December 31, 2023: March 31, December 31, Operating lease right-of-use assets (1) $ 24.2 $ 25.6 Operating lease liabilities (2) $ 26.6 $ 28.4 Weighted average lease term (years) 3.9 4.1 Weighted average discount rate 2.9 % 2.9 % (1) Operating lease right-of-use assets are included in other assets . (2) Operating lease liabilities are included in accounts payable, accrued expenses and other liabilities on the Company’s consolidated balance sheets .
Schedule of future minimum rental commitments	Future minimum rental commitments as of March 31, 2024 under these leases are expected to be as follows: Future Payments Remainder of 2024 $ 4.9 2025 5.8 2026 5.0 2027 4.1 2028 and thereafter 9.2 Total future annual minimum rental payments 29.0 Less: present value discount (2.4) Total lease liability as of March 31, 2024 $ 26.6

Significant transactions (Detai

Significant transactions (Details) $ in Millions	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 02, 2023	Sep. 30, 2022 USD ($)
Business Interruption Loss [Line Items]
Loss reserves			$ 905.6		$ 1,300
Reinsurance balances payable	$ 1,780.5	$ 1,736.7
Deferred gain on retroactive reinsurance	25.8	$ 27.9
Aggregate limit, percentage of booked reserves				1.30
Pallas Reinsurance Company Ltd.
Business Interruption Loss [Line Items]
Reinsurance balances payable	702.5
Reinsurance recoverable	$ 725.1

Segment reporting - Narrative (

Segment reporting - Narrative (Details)	3 Months Ended
	Mar. 31, 2024 segment
Segment Reporting [Abstract]
Number of operating segments	2

Segment reporting - Operating s

Segment reporting - Operating segment results (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Gross premiums written	$ 906.6	$ 1,110.5
Net premiums written	639.3	791.7
Net premiums earned	593.8	595.5
Loss and loss adjustment expenses incurred, net	317.5	267.1
Acquisition costs, net	144.9	119.7
Other underwriting expenses	41.8	52.2
Underwriting income	89.6	156.5
Services revenues	11.9	8.8
Services expenses	56	60
Noncontrolling income	(1.1)	(2.4)
Segment income	89.6	156.5
Net investment income	78.8	61.7
Net realized and unrealized investment gains	1	11.3
Net realized and unrealized investment gains from related party investment funds	0	0.8
Intangible asset amortization	(2.9)	(2.4)
Interest expense	(20.5)	(12.8)
Foreign exchange gains (losses)	3.7	(0.1)
Income before income tax expense	105.6	163.8
Income tax expense	(9.7)	(25.5)
Net income	95.9	138.3
Net income available to SiriusPoint	$ 94.8	$ 135.9
Underwriting Ratios:
Loss ratio	53.50%	44.90%
Acquisition cost ratio	24.40%	20.10%
Other underwriting expenses ratio	7%	8.80%
Combined ratio	84.90%	73.80%
Operating Segments
Segment Reporting Information [Line Items]
Gross premiums written	$ 880.7	$ 1,060.2
Net premiums written	627.2	763.6
Net premiums earned	517.8	550.7
Loss and loss adjustment expenses incurred, net	301.1	258.1
Acquisition costs, net	135	137.7
Other underwriting expenses	37.4	47.5
Underwriting income	44.3	107.4
Noncontrolling income	0	0
Segment income	62.4	124.1
Income before income tax expense	62.4	124.1
Income tax expense	0	0
Net income	62.4	124.1
Net income available to SiriusPoint	$ 62.4	$ 124.1
Underwriting Ratios:
Loss ratio	58.10%	46.90%
Acquisition cost ratio	26.10%	25%
Other underwriting expenses ratio	7.20%	8.60%
Combined ratio	91.40%	80.50%
Operating Segments | Services
Segment Reporting Information [Line Items]
Services revenues	$ 65.8	$ 63.8
Services expenses	46	45.5
Net services fee income	19.8	18.3
Noncontrolling income	(1.7)	(1.6)
Net income available to SiriusPoint	18.1	16.7
Eliminations
Segment Reporting Information [Line Items]
Gross premiums written	0	0
Net premiums written	0	0
Net premiums earned	0	0
Loss and loss adjustment expenses incurred, net	(1.4)	(1.3)
Acquisition costs, net	(33.2)	(32.5)
Other underwriting expenses	0	0
Underwriting income	34.6	33.8
Noncontrolling income	0	0
Segment income	(2.5)	(0.5)
Income before income tax expense	(2.5)	(0.5)
Income tax expense	0	0
Net income	(2.5)	(0.5)
Net income available to SiriusPoint	(2.5)	(0.5)
Eliminations | Services
Segment Reporting Information [Line Items]
Services revenues	(37.1)	(34.3)
Services expenses	0	0
Net services fee income	(37.1)	(34.3)
Noncontrolling income	0	0
Net income available to SiriusPoint	(37.1)	(34.3)
Corporate
Segment Reporting Information [Line Items]
Gross premiums written	25.9	50.3
Net premiums written	12.1	28.1
Net premiums earned	76	44.8
Loss and loss adjustment expenses incurred, net	17.8	10.3
Acquisition costs, net	43.1	14.5
Other underwriting expenses	4.4	4.7
Underwriting income	10.7	15.3
Services revenues	(16.8)	(20.7)
Services expenses	10	14.5
Noncontrolling income	0.6	(0.8)
Segment income	10.7	15.3
Net investment income	78.8	61.7
Net realized and unrealized investment gains	1	11.3
Net realized and unrealized investment gains from related party investment funds		0.8
Intangible asset amortization	(2.9)	(2.4)
Interest expense	(20.5)	(12.8)
Foreign exchange gains (losses)	3.7	(0.1)
Income before income tax expense	44	38.6
Income tax expense	(9.7)	(25.5)
Net income	34.3	13.1
Net income available to SiriusPoint	34.9	12.3
Segment Measure Reclass
Segment Reporting Information [Line Items]
Services revenues	28.7	29.5
Services expenses	46	45.5
Noncontrolling income	(1.7)	(1.6)
Segment income	19	17.6
Net realized and unrealized investment gains	0	0
Income before income tax expense	1.7	1.6
Income tax expense	0
Net income	1.7	1.6
Net income available to SiriusPoint	0	0
Segment Measure Reclass | Services
Segment Reporting Information [Line Items]
Services revenues	(28.7)	(29.5)
Services expenses	(46)	(45.5)
Net services fee income	17.3	16
Noncontrolling income	1.7	1.6
Net income available to SiriusPoint	19	17.6
Reinsurance | Operating Segments
Segment Reporting Information [Line Items]
Gross premiums written	356.4	396.2
Net premiums written	290.1	311
Net premiums earned	253.6	259.5
Loss and loss adjustment expenses incurred, net	124.6	85.6
Acquisition costs, net	69.8	66
Other underwriting expenses	19.3	28.2
Underwriting income	39.9	79.7
Segment income	39.9	79.9
Income before income tax expense	$ 39.9	$ 79.9
Underwriting Ratios:
Loss ratio	49.10%	33%
Acquisition cost ratio	27.50%	25.40%
Other underwriting expenses ratio	7.60%	10.90%
Combined ratio	84.20%	69.30%
Reinsurance | Operating Segments | Services
Segment Reporting Information [Line Items]
Services revenues	$ 0	$ 0.2
Services expenses	0	0
Net services fee income	0	0.2
Noncontrolling income	0	0
Net income available to SiriusPoint	0	0.2
Insurance & Services | Operating Segments
Segment Reporting Information [Line Items]
Gross premiums written	524.3	664
Net premiums written	337.1	452.6
Net premiums earned	264.2	291.2
Loss and loss adjustment expenses incurred, net	176.5	172.5
Acquisition costs, net	65.2	71.7
Other underwriting expenses	18.1	19.3
Underwriting income	4.4	27.7
Segment income	22.5	44.2
Income before income tax expense	$ 22.5	$ 44.2
Underwriting Ratios:
Loss ratio	66.80%	59.20%
Acquisition cost ratio	24.70%	24.60%
Other underwriting expenses ratio	6.90%	6.60%
Combined ratio	98.40%	90.40%
Insurance & Services | Operating Segments | Services
Segment Reporting Information [Line Items]
Services revenues	$ 65.8	$ 63.6
Services expenses	46	45.5
Net services fee income	19.8	18.1
Noncontrolling income	(1.7)	(1.6)
Net income available to SiriusPoint	$ 18.1	$ 16.5

Cash, cash equivalents, restr_3

Cash, cash equivalents, restricted cash and restricted investments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 867.5	$ 969.2
Restricted cash	218.9	132.1
Total cash, cash equivalents and restricted cash	1,086.4	1,101.3	$ 974.6	$ 913.7
Restricted investments securing reinsurance contracts and letter of credit facilities	2,658.5	2,668
Total cash, cash equivalents, restricted cash and restricted investments	3,744.9	3,769.3
Managing general underwriters
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	29.1	22.5
Letter of credit facilities
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	70.2	56.9
Reinsurance contracts
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 119.6	$ 52.7

Fair value measurements - Inves

Fair value measurements - Investments categorized by the level of the fair value hierarchy (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets
Debt securities, available-for-sale	$ 5,057.5	$ 4,755.4
Debt securities, trading	406	534.9
Equity securities	1.6	1.6
Short-term investments	329.9	371.6
Other long-term investments	296.6	308.5
Cost and equity method investments	73.6	80.1
Total assets	6,198.6	6,093.3
Liabilities
Securities sold under an agreement to repurchase		67.3
Liability-classified capital instruments	83.2	67.3
Derivative liabilities	20.6	6.4
Total liabilities	103.8	73.7
Asset-backed securities
Assets
Debt securities, available-for-sale	1,044	880.7
Debt securities, trading	199.7	256.6
Residential mortgage-backed securities
Assets
Debt securities, available-for-sale	926.8	902.8
Debt securities, trading	55.3	57.2
Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	236.5	204.1
Debt securities, trading	66.2	67.8
Corporate debt securities
Assets
Debt securities, available-for-sale	1,730.8	1,573.1
Debt securities, trading	41.5	45.2
U.S. government and government agency
Assets
Debt securities, available-for-sale	1,069.5	1,136.7
Debt securities, trading	33.4	98.1
Non-U.S. government and government agency
Assets
Debt securities, available-for-sale	49.9	58
Debt securities, trading	9.9	10
Fair Value, Inputs, Level 1, 2 and 3
Assets
Debt securities, available-for-sale	5,057.5	4,755.4
Debt securities, trading	406	534.9
Equity securities	1.6	1.6
Short-term investments	329.9	371.6
Other long-term investments	170.6	169.7
Derivative assets	1.4	15.7
Total assets	5,967	5,848.9
Fair Value, Inputs, Level 1, 2 and 3 | Asset-backed securities
Assets
Debt securities, available-for-sale	1,044	880.7
Debt securities, trading	199.7	256.6
Fair Value, Inputs, Level 1, 2 and 3 | Residential mortgage-backed securities
Assets
Debt securities, available-for-sale	926.8	902.8
Debt securities, trading	55.3	57.2
Fair Value, Inputs, Level 1, 2 and 3 | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	236.5	204.1
Debt securities, trading	66.2	67.8
Fair Value, Inputs, Level 1, 2 and 3 | Corporate debt securities
Assets
Debt securities, available-for-sale	1,730.8	1,573.1
Debt securities, trading	41.5	45.2
Fair Value, Inputs, Level 1, 2 and 3 | U.S. government and government agency
Assets
Debt securities, available-for-sale	1,069.5	1,136.7
Debt securities, trading	33.4	98.1
Fair Value, Inputs, Level 1, 2 and 3 | Non-U.S. government and government agency
Assets
Debt securities, available-for-sale	49.9	58
Debt securities, trading	9.9	10
Quoted prices in active markets (Level 1)
Assets
Debt securities, available-for-sale	1,066.6	1,132.6
Debt securities, trading	33.4	98.1
Equity securities	1.6	1.6
Short-term investments	295.2	321.9
Other long-term investments	0	0
Derivative assets	0	0
Total assets	1,396.8	1,554.2
Liabilities
Securities sold under an agreement to repurchase		0
Liability-classified capital instruments	0
Derivative liabilities	0	0
Total liabilities	0	0
Quoted prices in active markets (Level 1) | Asset-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | Residential mortgage-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | Corporate debt securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Quoted prices in active markets (Level 1) | U.S. government and government agency
Assets
Debt securities, available-for-sale	1,066.6	1,132.6
Debt securities, trading	33.4	98.1
Quoted prices in active markets (Level 1) | Non-U.S. government and government agency
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant other observable inputs (Level 2)
Assets
Debt securities, available-for-sale	3,990.9	3,622.8
Debt securities, trading	372.6	436.8
Equity securities	0	0
Short-term investments	34.7	49.7
Other long-term investments	0	0
Derivative assets	0	0
Total assets	4,398.2	4,109.3
Liabilities
Securities sold under an agreement to repurchase		0
Liability-classified capital instruments	0
Derivative liabilities	0	0
Total liabilities	0	0
Significant other observable inputs (Level 2) | Asset-backed securities
Assets
Debt securities, available-for-sale	1,044	880.7
Debt securities, trading	199.7	256.6
Significant other observable inputs (Level 2) | Residential mortgage-backed securities
Assets
Debt securities, available-for-sale	926.8	902.8
Debt securities, trading	55.3	57.2
Significant other observable inputs (Level 2) | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	236.5	204.1
Debt securities, trading	66.2	67.8
Significant other observable inputs (Level 2) | Corporate debt securities
Assets
Debt securities, available-for-sale	1,730.8	1,573.1
Debt securities, trading	41.5	45.2
Significant other observable inputs (Level 2) | U.S. government and government agency
Assets
Debt securities, available-for-sale	2.9	4.1
Debt securities, trading	0	0
Significant other observable inputs (Level 2) | Non-U.S. government and government agency
Assets
Debt securities, available-for-sale	49.9	58
Debt securities, trading	9.9	10
Significant unobservable inputs (Level 3)
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Equity securities	0	0
Short-term investments	0	0
Other long-term investments	170.6	169.7
Derivative assets	1.4	15.7
Total assets	172	185.4
Liabilities
Securities sold under an agreement to repurchase		67.3
Liability-classified capital instruments	83.2
Derivative liabilities	20.6	6.4
Total liabilities	103.8	73.7
Significant unobservable inputs (Level 3) | Asset-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Residential mortgage-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Commercial mortgage-backed securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Corporate debt securities
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | U.S. government and government agency
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Significant unobservable inputs (Level 3) | Non-U.S. government and government agency
Assets
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Valued at NAV
Assets
Investments in funds valued at NAV	$ 158	$ 164.3

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, 2024	Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 185.4	$ 240
Transfers in to (out of) Level 3	0	0
Purchases	0	2.9
Sales & Settlements	(4.6)	(2.1)
Realized and Unrealized Gains (Losses)	(8.8)	1.1
Ending balance	172	241.9
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(73.7)	(30)
Transfers in to (out of) Level 3	0	0
Purchases	0	(3.2)
Sales & Settlements	(1.1)	1.5
Realized and Unrealized Gains (Losses)	(29)	(23.7)
Ending balance	(103.8)	(55.4)
Liability-classified capital instruments
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(67.3)	(21.4)
Transfers in to (out of) Level 3	0	0
Purchases	0	0
Sales & Settlements	0	0
Realized and Unrealized Gains (Losses)	(15.9)	(25.6)
Ending balance	(83.2)	(47)
Derivative liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(6.4)	(8.6)
Transfers in to (out of) Level 3	0	0
Purchases	0	(3.2)
Sales & Settlements	(1.1)	1.5
Realized and Unrealized Gains (Losses)	(13.1)	1.9
Ending balance	(20.6)	(8.4)
Preferred stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		3.2
Transfers in to (out of) Level 3		0
Purchases		0
Sales & Settlements		0
Realized and Unrealized Gains (Losses)		0
Ending balance		3.2
Other long-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	169.7	227.3
Transfers in to (out of) Level 3	0	0
Purchases	0	0.4
Sales & Settlements	0	0
Realized and Unrealized Gains (Losses)	0.9	(0.3)
Ending balance	170.6	227.4
Derivative assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	15.7	9.5
Transfers in to (out of) Level 3	0	0
Purchases	0	2.5
Sales & Settlements	(4.6)	(2.1)
Realized and Unrealized Gains (Losses)	(9.7)	1.4
Ending balance	$ 1.4	$ 11.3

Fair value measurements - Finan

Fair value measurements - Financial instruments not measured at fair value (Details) - Level 2 - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value | Series B preference shares
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Series B preference shares	$ 202.6	$ 197.4
Fair Value | Subordinated Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	214	206.6
Fair Value | Senior Notes | 2016 Senior Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	382	370
Fair Value | Senior Notes | 2015 Senior Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	113.9	115.2
Carrying Value | Series B preference shares
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Series B preference shares	200	200
Carrying Value | Subordinated Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	252.6	267.9
Carrying Value | Senior Notes | 2016 Senior Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	403.2	403.5
Carrying Value | Senior Notes | 2015 Senior Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Long-term debt	$ 114.8	$ 114.8

Investments - Summary of debt s

Investments - Summary of debt securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt securities, available for sale
Cost or amortized cost	$ 5,075.4	$ 4,754.6
Gross unrealized gains	31.4	42.9
Gross unrealized losses	(48.7)	(41.2)
Net foreign currency gains (losses)	(0.6)	(0.9)
Fair value	5,057.5	4,755.4
Debt securities, trading
Cost or amortized cost	433.3	568.1
Gross unrealized gains	0.7	0.7
Gross unrealized losses	(28)	(33.9)
Net foreign currency gains (losses)	0	0
Fair value	406	534.9
Debt securities, available for sale, allowance for credit losses	0	0
Asset-backed securities
Debt securities, available for sale
Cost or amortized cost	1,040.7	882.2
Gross unrealized gains	9.5	7.8
Gross unrealized losses	(6.2)	(9.3)
Net foreign currency gains (losses)	0	0
Fair value	1,044	880.7
Debt securities, trading
Cost or amortized cost	203	261.1
Gross unrealized gains	0.6	0.6
Gross unrealized losses	(3.9)	(5.1)
Net foreign currency gains (losses)	0	0
Fair value	199.7	256.6
Residential mortgage-backed securities
Debt securities, available for sale
Cost or amortized cost	930.9	903
Gross unrealized gains	12.9	15.8
Gross unrealized losses	(17)	(16)
Net foreign currency gains (losses)	0	0
Fair value	926.8	902.8
Debt securities, trading
Cost or amortized cost	64.1	67
Gross unrealized gains	0	0
Gross unrealized losses	(8.8)	(9.8)
Net foreign currency gains (losses)	0	0
Fair value	55.3	57.2
Commercial mortgage-backed securities
Debt securities, available for sale
Cost or amortized cost	236.9	204
Gross unrealized gains	1.4	1.6
Gross unrealized losses	(1.8)	(1.5)
Net foreign currency gains (losses)	0	0
Fair value	236.5	204.1
Debt securities, trading
Cost or amortized cost	73.2	76.7
Gross unrealized gains	0.1	0.1
Gross unrealized losses	(7.1)	(9)
Net foreign currency gains (losses)	0	0
Fair value	66.2	67.8
Corporate debt securities
Debt securities, available for sale
Cost or amortized cost	1,739.4	1,569.6
Gross unrealized gains	5.9	12
Gross unrealized losses	(14.1)	(7.5)
Net foreign currency gains (losses)	(0.4)	(1)
Fair value	1,730.8	1,573.1
Debt securities, trading
Cost or amortized cost	48.7	52.2
Gross unrealized gains	0	0
Gross unrealized losses	(7.2)	(7)
Net foreign currency gains (losses)	0	0
Fair value	41.5	45.2
U.S. government and government agency
Debt securities, available for sale
Cost or amortized cost	1,077	1,137.8
Gross unrealized gains	1.7	5.5
Gross unrealized losses	(9.2)	(6.6)
Net foreign currency gains (losses)	0	0
Fair value	1,069.5	1,136.7
Debt securities, trading
Cost or amortized cost	34.1	100.8
Gross unrealized gains	0	0
Gross unrealized losses	(0.7)	(2.7)
Net foreign currency gains (losses)	0	0
Fair value	33.4	98.1
Non-U.S. government and government agency
Debt securities, available for sale
Cost or amortized cost	50.5	58
Gross unrealized gains	0	0.2
Gross unrealized losses	(0.4)	(0.3)
Net foreign currency gains (losses)	(0.2)	0.1
Fair value	49.9	58
Debt securities, trading
Cost or amortized cost	10.2	10.3
Gross unrealized gains	0	0
Gross unrealized losses	(0.3)	(0.3)
Net foreign currency gains (losses)	0	0
Fair value	$ 9.9	$ 10

Investments - Narrative (Detail

Investments - Narrative (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Debt and Equity Securities, FV-NI [Line Items]
Number of available-for-sale investment securities in the twelve month or more category (security) | security	735	713
Available-for-sale investment securities in the twelve month or more category	$ 542,300,000	$ 556,900,000
Available-for-sale investment securities in the twelve month or more category, unrealized loss	$ 20,000,000	$ 20,300,000
Weighted average duration of debt securities	2 years 10 months 24 days	2 years 9 months 18 days
Third Point Enhanced LP
Debt and Equity Securities, FV-NI [Line Items]
Unfunded commitments	$ 0
Third Point Venture Offshore Fund I LP
Debt and Equity Securities, FV-NI [Line Items]
Unfunded commitments	$ 9,500,000
Percentage of net asset value held	16.80%
Third Point Venture Offshore Fund II LP
Debt and Equity Securities, FV-NI [Line Items]
Unfunded commitments	$ 21,600,000
Percentage of net asset value held	17.80%
Related Party
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	$ 587,200,000	$ 562,000,000
Sub-prime
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	192,500,000	185,100,000
Sub-prime | AAA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	101,300,000	117,500,000
Sub-prime | AA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	57,900,000	37,700,000
Sub-prime | A
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	5,700,000	12,300,000
Sub-prime | BBB
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	17,800,000	13,300,000
Sub-prime | Unrated
Debt and Equity Securities, FV-NI [Line Items]
Debt securities	$ 9,800,000	$ 4,300,000

Investments - Debt securities b

Investments - Debt securities by contractual maturity (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt securities, AFS - Cost or amortized cost
Due in one year or less	$ 460.3	$ 358.6
Due after one year through five years	2,131.5	2,221
Due after five years through ten years	272.4	183.3
Due after ten years	2.7	2.5
Cost or amortized cost	5,075.4	4,754.6
Debt securities, AFS - Fair value
Due in one year or less	457.7	357.2
Due after one year through five years	2,116	2,219.8
Due after five years through ten years	274.2	188.5
Due after ten years	2.3	2.3
Debt securities, available for sale	5,057.5	4,755.4
Debt securities, trading - Cost or Amortized cost
Due in one year or less	14.2	80.2
Due after one year through five years	32.9	37.2
Due after five years through ten years	19.4	19.4
Due after ten years	26.5	26.6
Cost or amortized cost	433.3	568.1
Debt securities, trading - Fair value
Due in one year or less	14	79.7
Due after one year through five years	32.2	34.5
Due after five years through ten years	17.9	18
Due after ten years	20.8	21.3
Debt securities, trading	406	534.9
Mortgage-backed and asset-backed securities
Debt securities, AFS - Cost or amortized cost
Without single maturity date	2,208.5	1,989.2
Debt securities, AFS - Fair value
Without single maturity date	2,207.3	1,987.6
Debt securities, trading - Cost or Amortized cost
Without single maturity date	340.3	404.7
Debt securities, trading - Fair value
Without single maturity date	$ 321.1	$ 381.4

Investments - Ratings and fair

Investments - Ratings and fair value of debt securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	$ 5,057.5	$ 4,755.4
Debt securities, trading	406	534.9
AAA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	796.6	730.4
Debt securities, trading	197.4	248.4
AA
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	2,378.8	2,334.4
Debt securities, trading	110.1	177
A
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	1,312.2	1,122.1
Debt securities, trading	19.3	28.9
BBB
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	485.5	515.5
Debt securities, trading	70.9	71.7
Other
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, available-for-sale	84.4	53
Debt securities, trading	$ 8.3	$ 8.9

Investments - Summary of equity

Investments - Summary of equity securities and other long-term investments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Equity securities, Cost or amortized cost	$ 1.6	$ 1.9
Equity securities, Gross unrealized gains	0	0
Equity securities, Gross unrealized losses	(0.2)	(0.5)
Equity securities, Net foreign currency gains	0.2	0.2
Equity securities, Fair value	1.6	1.6
Other long-term investments, Cost or amortized cost	343.1	356.2
Other long-term investments, Gross unrealized gains	20.7	20
Other long-term investments, Gross unrealized losses	(70.3)	(70.1)
Other long-term investments, net foreign currency gains	3.1	2.4
Other Long-Term Investments	$ 296.6	$ 308.5

Investments - Equity securities

Investments - Equity securities and other-long term investments at fair value (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	$ 296.6	$ 308.5
Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	170.6	169.7
Hedge funds and private equity funds
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	70.1	74.5
Hedge funds and private equity funds | Valued at NAV
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	52.2	58.7
Hedge funds and private equity funds | Valued at Level 3
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	0
Strategic investments
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	196.4	203.9
Other investments
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	30.1	30.1
Strategic investments and Limited liability companies and private equity securities
Debt and Equity Securities, FV-NI [Line Items]
Unfunded commitments	$ 12.1	$ 14.7

Investments - Investments in un

Investments - Investments in unconsolidated entities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	$ 296.6	$ 308.5
Equity method eligible unconsolidated entities, using the fair value option
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	139	139.2
Equity method investments
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	40.9	37
Other unconsolidated investments, at fair value
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	84	89.2
Other unconsolidated investments, at cost
Debt and Equity Securities, FV-NI [Line Items]
Other long-term investments	$ 32.7	$ 43.1

Investments - Investment in rel

Investments - Investment in related party investment funds (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, at fair value	$ 105.6	$ 105.6
Related Party
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, at fair value	105.6	105.6
Third Point Enhanced LP | Related Party
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, at fair value	77.8	77.5
Third Point Venture Offshore Fund I LP | Related Party
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, at fair value	24.7	25
Third Point Venture Offshore Fund II LP | Related Party
Debt and Equity Securities, FV-NI [Line Items]
Investments in related party investment funds, at fair value	$ 3.1	$ 3.1

Total net investment income a_3

Total net investment income and realized and unrealized investment gains - Summary of net investment income and total realized and unrealized investment gains (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Investment expenses	$ (3.9)	$ (5.4)
Net investment income and net realized and unrealized investment gains	79.8	73.8
Debt securities, available for sale
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	63.7	35.1
Debt securities, trading
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	8.8	29.1
Short-term investments
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	4.4	8.4
Other long-term investments
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	0.5	4.4
Derivative instruments
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	1.3	0
Related party investment funds
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	0	0.8
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	78.7	77.8
Net investment income on cash and cash equivalents
Net Investment Income [Line Items]
Net investment income and realized and unrealized investment gains before other investment expenses and investment income on cash and cash equivalents	$ 5	$ 1.4

Total net investment income a_4

Total net investment income and realized and unrealized investment gains - Summary of net realized and unrealized gains on investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 5.5	$ 5.8
Gross realized losses	(9.2)	(15.6)
Net realized losses on investments	(3.7)	(9.8)
Net unrealized gains on investments	4.7	21.1
Net realized and unrealized gains on investments	1	11.3
Realized and unrealized gains (losses) from related party investments	$ (1.9)	$ 1.8

Total net investment income a_5

Total net investment income and realized and unrealized investment gains - Summary of net realized investment losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Debt securities, available for sale	$ (0.3)	$ (0.6)
Debt securities, trading	(3.4)	(7.4)
Short-term investments	0.6	(0.2)
Other long-term investments	(0.8)	(0.4)
Net investment income (loss) on cash and cash equivalents	0.2	(1.2)
Net realized losses on investments	$ (3.7)	$ (9.8)

Total net investment income a_6

Total net investment income and realized and unrealized investment gains - Summary of net realized investment gains on other long-term investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Net realized investment losses on Other long-term investments	$ (3.7)	$ (9.8)
Other long-term investments
Net Investment Income [Line Items]
Net realized investment losses on Other long-term investments	(0.8)	(0.4)
Hedge funds and private equity funds
Net Investment Income [Line Items]
Net realized investment losses on Other long-term investments	1	(0.4)
Strategic investments
Net Investment Income [Line Items]
Net realized investment losses on Other long-term investments	$ (1.8)	$ 0

Total net investment income a_7

Total net investment income and realized and unrealized investment gains - Summary of net unrealized investment gains (losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Debt securities, trading	$ 5.4	$ 23
Short-term investments	(0.9)	(0.4)
Derivative instruments	1	0
Other long-term investments	1.3	(3)
Net investment income (loss) on cash and cash equivalents	(2.1)	1.5
Net unrealized investment gains (losses)	$ 4.7	$ 21.1

Total net investment income a_8

Total net investment income and realized and unrealized investment gains - Summary of net unrealized investment gains (losses) on other long-term investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Net unrealized investment gains (losses) on Other long-term investments	$ 1.3	$ (3)
Hedge funds and private equity funds
Net Investment Income [Line Items]
Net unrealized investment gains (losses) on Other long-term investments	(0.6)	0.9
Strategic investments
Net Investment Income [Line Items]
Net unrealized investment gains (losses) on Other long-term investments	$ 1.9	$ (3.9)

Total net investment income a_9

Total net investment income and realized and unrealized investment gains - Summary of gains (losses)attributable to unrealized investment gains on level 3 investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Debt securities, trading	$ 5.4	$ 23
Other long-term investments	1.3	(3)
Net unrealized investment gains (losses)	4.7	21.1
Level 3
Net Investment Income [Line Items]
Debt securities, trading	0	0.1
Other long-term investments	1.1	(4.8)
Net unrealized investment gains (losses)	$ 1.1	$ (4.7)

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Foreign exchange contract
Derivative [Line Items]
Collateral pledged	$ 42	$ 42.2
Credit default swap
Derivative [Line Items]
Collateral pledged	$ 20.5	$ 22.3

Derivatives - Classification an

Derivatives - Classification and fair value of derivatives (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Derivative liabilities at fair value	$ 20.6	$ 6.4
Derivatives not designated as hedging instruments | Foreign currency forwards
Derivative [Line Items]
Derivative assets at fair value	1.1	12
Derivative liabilities at fair value	6.9	0
Notional Value	808.6	585.3
Derivatives not designated as hedging instruments | Weather derivatives
Derivative [Line Items]
Derivative assets at fair value	0.1	0.2
Derivative liabilities at fair value	5.1	1
Notional Value	20.4	30.6
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Derivative assets at fair value	0.1	3.4
Derivative liabilities at fair value	0	1.7
Notional Value	62.7	62.7
Derivatives not designated as hedging instruments | Credit default swap
Derivative [Line Items]
Derivative assets at fair value	0.1	0.1
Derivative liabilities at fair value	0	0
Notional Value	30	30
Derivatives not designated as hedging instruments | Reinsurance contracts accounted for as derivatives
Derivative [Line Items]
Derivative assets at fair value	0	0
Derivative liabilities at fair value	8.6	3.7
Notional Value	$ 94.3	$ 97.4

Derivatives - Classification _2

Derivatives - Classification and net impact on earnings of derivatives (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	$ (17.4)	$ (1.6)
Weather derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	(1.5)	3.5
Foreign currency swaps
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	0	(1.6)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	1.3	0
Reinsurance contracts accounted for as derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net impact on earnings	$ (4.8)	$ 0.1

Variable and voting interest _3

Variable and voting interest entities - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2023	Mar. 31, 2024	Dec. 31, 2022	Dec. 31, 2023
Variable Interest Entity [Line Items]
Assets		$ 13,135.8		$ 12,871.5
Liabilities		10,515.4		10,340.9
Alstead Re
Variable Interest Entity [Line Items]
Assets		14.7		14.5
Liabilities		9.4		9.2
Arcadian
Variable Interest Entity [Line Items]
Assets		142.9		150.9
Liabilities		$ 113.5		123.8
VIE, ownership percentage		49%
Maximum financial exposure		$ 18
Banyan
Variable Interest Entity [Line Items]
VIE, ownership percentage	49%		100%
Alta Signa
Variable Interest Entity [Line Items]
Assets		3.2		2.8
Liabilities		$ 0.7		$ 0.8
VOE, ownership percentage		75.10%
TP Enhanced Fund | TP Enhanced Fund
Variable Interest Entity [Line Items]
VIE, ownership percentage		89.30%
Variable interest entity, primary beneficiary | TP Enhanced Fund | TP GP
Variable Interest Entity [Line Items]
VIE, ownership percentage		10.70%

Variable and voting interest _4

Variable and voting interest entities - Reconciliation of noncontrolling interests (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance, beginning of period	$ 16.7	$ 7.9
Net income attributable to noncontrolling interests	1.1	2.4
Contributions	0	1.1
Balance, end of period	$ 17.8	$ 11.4

Variable and voting interest _5

Variable and voting interest entities - Total assets and maximum exposure to loss for unconsolidated variable interest entities (Details) - Other long-term investments - Variable Interest Entity, Not Primary Beneficiary, Excluding Investments In Related Party Investment Funds - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Total VIE Assets
Total VIE Assets	$ 175.8	$ 189.8
Maximum Exposure to Loss
On-Balance Sheet	126.2	126.2
Off-Balance Sheet	1.9	5.7
Total	$ 128.1	$ 131.9

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, 2024	Mar. 31, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves for loss and loss adjustment expenses, beginning of period	$ 5,608.1	$ 5,268.7
Less: loss and loss adjustment expenses recoverable, beginning of period	(2,295.1)	(1,376.2)
Less: deferred charges on retroactive reinsurance contracts	27.5	(1)
Net reserves for loss and loss adjustment expenses, beginning of period	3,340.5	3,891.5
Increase (decrease) in net loss and loss adjustment expenses incurred in respect of losses occurring in:
Current year	356.4	372.5
Prior years	(38.9)	(105.4)
Total incurred loss and loss adjustment expenses	317.5	267.1
Net loss and loss adjustment expenses paid in respect of losses occurring in:
Current year	(44)	(36.4)
Prior years	(272.8)	(202.1)
Total net paid losses	(316.8)	(238.5)
Foreign currency translation	15.8	6
Net reserves for loss and loss adjustment expenses, end of period	3,357	3,926.1
Plus: loss and loss adjustment expenses recoverable, end of period	2,233.8	1,392
Plus: deferred (gains) charges on retroactive reinsurance	(25.5)	0.8
Gross reserves for loss and loss adjustment expenses, end of period	$ 5,565.3	$ 5,318.9

Loss and loss adjustment expe_4

Loss and loss adjustment expense reserves - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Insurance [Abstract]
Favorable change in prior loss year reserve development	$ 38.9	$ 105.4

Allowance for expected credit_3

Allowance for expected credit losses - Summary of allowance for expected credit losses (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Receivables [Abstract]
Insurance and reinsurance balances receivable, net	$ 2,127.2	$ 1,966.3
Loss and loss adjustment expenses recoverable, net	2,233.8	2,295.1	$ 1,392	$ 1,376.2
Other assets	84.6	76.8
Total assets in scope	$ 4,445.6	$ 4,338.2

Allowance for expected credit_4

Allowance for expected credit losses - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for expected credit losses	$ 28,800,000		$ 28,800,000
Current expected credit (gains) losses	$ 0	$ 0
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	69%
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	84%

Debt and letter of credit fac_3

Debt and letter of credit facilities - Summary of debt obligations (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total debt	$ 770.6	$ 786.2
Subordinated Notes
Debt Instrument [Line Items]
Debt, at face value	257.8	273.6
Unamortized discount	(5.2)	(5.7)
Total debt	$ 252.6	$ 267.9
Effective rate	8.20%	7.70%
Senior Notes | 2016 Senior Notes
Debt Instrument [Line Items]
Debt, at face value	$ 400	$ 400
Unamortized premium	3.2	3.5
Total debt	$ 403.2	$ 403.5
Effective rate	4.30%	4.60%
Senior Notes | 2015 Senior Notes
Debt Instrument [Line Items]
Debt, at face value	$ 115	$ 115
Unamortized issuance costs	(0.2)	(0.2)
Total debt	$ 114.8	$ 114.8
Effective rate	7%	7%

Debt and letter of credit fac_4

Debt and letter of credit facilities - Narrative (Details) - USD ($)		1 Months Ended	3 Months Ended
	Feb. 26, 2021	Feb. 29, 2024	Mar. 31, 2024	Mar. 31, 2023	Apr. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Interest expense			$ 11,800,000	$ 12,800,000
Funds withheld			$ 7,100,000	$ 0
Senior Notes Due 2029 | Senior Notes | Subsequent event
Debt Instrument [Line Items]
Face value of debt issued					$ 400,000,000
Effective rate					7%
2016 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Effective rate			4.30%			4.60%
Debt, at face value			$ 400,000,000			$ 400,000,000
2016 Senior Notes | Senior Notes | Subsequent event
Debt Instrument [Line Items]
Effective rate					4.60%
Senior notes redeemed					$ 400,000,000
2015 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Effective rate			7%			7%
Debt, at face value			$ 115,000,000			$ 115,000,000
2015 Senior Notes | Senior Notes | Subsequent event
Debt Instrument [Line Items]
Senior notes redeemed					$ 115,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Contractual term	3 years
Maximum borrowing capacity	$ 300,000,000
Extension term		1 year
Outstanding borrowings			$ 0

Debt and letter of credit fac_5

Debt and letter of credit facilities - Summary of letter of credit facilities (Details) - USD ($)	Mar. 31, 2024	Feb. 26, 2021
Standby letters of credit
Line of Credit Facility [Line Items]
Issued	$ 1,263,800,000
Standby letters of credit | Cash and Cash Equivalents
Line of Credit Facility [Line Items]
Collateral	70,200,000
Standby letters of credit | Debt securities
Line of Credit Facility [Line Items]
Collateral	1,423,400,000
Standby letters of credit | Committed - Secured letters of credit facilities
Line of Credit Facility [Line Items]
Committed Capacity	355,000,000
Issued	279,600,000
Standby letters of credit | Committed - Secured letters of credit facilities | Cash and Cash Equivalents
Line of Credit Facility [Line Items]
Collateral	16,400,000
Standby letters of credit | Committed - Secured letters of credit facilities | Debt securities
Line of Credit Facility [Line Items]
Collateral	225,400,000
Standby letters of credit | Uncommitted - Secured letters of credit facilities
Line of Credit Facility [Line Items]
Issued	984,200,000
Standby letters of credit | Uncommitted - Secured letters of credit facilities | Cash and Cash Equivalents
Line of Credit Facility [Line Items]
Collateral	53,800,000
Standby letters of credit | Uncommitted - Secured letters of credit facilities | Debt securities
Line of Credit Facility [Line Items]
Collateral	$ 1,198,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Committed Capacity		$ 300,000,000

Income taxes (Details)

Income taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 9.7	$ 25.5
Pre-tax income (loss)	$ 105.6	$ 163.8
Effective tax rate	9.20%
Unrecognized tax benefits	$ 2.3
Unrecognized tax benefits that would impact the effective tax rate	$ 1.6

Shareholders' equity - Common s

Shareholders' equity - Common shares issued and outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Movement In Common Stock Outstanding [Roll Forward]
Common shares issued, beginning of period (in shares)	168,120,022
Common shares outstanding, beginning of period (in shares)	168,120,022
Common shares issued, end of period (in shares)	169,753,232
Common shares outstanding, end of period (in shares)	169,753,232
Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Common shares issued, beginning of period (in shares)	168,120,022	162,177,653
Common shares outstanding, beginning of period (in shares)	168,120,022	162,177,653
Issuance of common shares upon exercise of options (in shares)	1,610,623	0
Common shares issued, end of period (in shares)	169,753,232	162,367,173
Common shares outstanding, end of period (in shares)	169,753,232	162,367,173
Restricted share awards | Common Stock
Movement In Common Stock Outstanding [Roll Forward]
Shares issued, net of forfeitures and shares withheld (in shares)	22,587	189,520

Shareholders' equity - Narrativ

Shareholders' equity - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) period director $ / shares shares	Mar. 31, 2023 USD ($)	Dec. 31, 2023 $ / shares shares
Class of Stock [Line Items]
Common shares authorized (in shares)	300,000,000
Common shares, par value (in dollars per share) | $ / shares	$ 0.10
Dividends paid to common shareholders | $	$ 0	$ 0
Dividends paid to preference shareholders | $	$ 4	4
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
Preference shares, shares outstanding (in shares)	8,000,000
Dividend rate	8%
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%
Rating agency triggering event, redemption percentage	102%
Capital disqualification triggering event, redemption percentage	100%
Tax triggering event, redemption percentage	100%
Dividends paid to preference shareholders | $	$ 4	$ 4
Series B preference shares | 5-year U.S. treasury rate
Class of Stock [Line Items]
Dividend rate basis spread on variable rate	7.298%

Earnings per share available _3

Earnings per share available to SiriusPoint common shareholders - Computation of basic and diluted earnings per share available to SiriusPoint common shareholders (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Weighted-average number of common shares outstanding:
Basic number of common shares outstanding (in shares)	168,934,114	160,905,860
Dilutive effect of warrants (in shares)	1,605,246	0
Diluted number of common shares outstanding (in shares)	174,380,963	164,130,946
Basic earnings per common share:
Net income available to SiriusPoint common shareholders	$ 90.8	$ 131.9
Net income allocated to SiriusPoint participating shareholders	(6.1)	(10)
Net income available to SiriusPoint common shareholders	$ 84.7	$ 121.9
Basic earnings per share available to SiriusPoint common shareholders (in dollars per share)	$ 0.50	$ 0.76
Diluted earnings per common share:
Net income available to SiriusPoint common shareholders	$ 90.8	$ 131.9
Net income allocated to SiriusPoint participating shareholders	(6.1)	(10)
Net income allocated to SiriusPoint common shareholders	$ 84.7	$ 121.9
Diluted earnings per share available to SiriusPoint common shareholders (in dollars per share)	$ 0.49	$ 0.74
Options
Weighted-average number of common shares outstanding:
Dilutive effect of share-based payment awards (in shares)	1,030,515	138,464
Restricted share awards and units
Weighted-average number of common shares outstanding:
Dilutive effect of share-based payment awards (in shares)	2,811,088	3,086,622

Earnings per share available _4

Earnings per share available to SiriusPoint common shareholders - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)	0
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)		3,910,700
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)		32,516,293
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)		48,900

Related party transactions - Na

Related party transactions - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Jun. 30, 2022	Feb. 23, 2022	Mar. 01, 2021	Feb. 26, 2021	Jan. 01, 2019
Related Party Transaction [Line Items]
Gross premiums written	$ 906,600,000	$ 1,110,500,000
Due to related party	2,127,200,000		$ 1,966,300,000
Due from related party	1,780,500,000		1,736,700,000
Management fees | Third Point LLC, 2022 LPA
Related Party Transaction [Line Items]
Fee percentage, annual					1.25%
Management fees | Third Point LLC, 2022 Venture II LPA
Related Party Transaction [Line Items]
Fee percentage, annual				0.75%
Management fees | Third Point LLC, TPIPS IMA
Related Party Transaction [Line Items]
Fee percentage, annual							0.06%
Management fees | Third Point LLC, 2022 IMA
Related Party Transaction [Line Items]
Fee percentage, annual					0.50%
Advisory fees | Third Point LLC, 2022 IMA
Related Party Transaction [Line Items]
Fee amount, annual					$ 1,500,000
Performance fees | TP GP
Related Party Transaction [Line Items]
Fee percentage, annual								20%
Performance fees | TP Venture GP
Related Party Transaction [Line Items]
Fee percentage, annual						20%
Performance fees | TP Venture GP II
Related Party Transaction [Line Items]
Fee percentage, annual				20%
Incentive fees | Third Point LLC, 2022 IMA
Related Party Transaction [Line Items]
Fee percentage, annual					15%
Related Party
Related Party Transaction [Line Items]
Gross premiums written	17,000,000	$ 67,500,000
Due to related party	56,300,000		61,800,000
Due from related party	$ 0		$ 0

Related party transactions - In

Related party transactions - Investments managed by related parties (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Investments in related party investment funds, at fair value	$ 105.6	$ 105.6
Total investments	6,197.2	6,077.6
Related Party
Related Party Transaction [Line Items]
Investments in related party investment funds, at fair value	105.6	105.6
Third Point Optimized Credit Portfolio	587.2	562
Total investments	692.8	667.6
Related Party | Third Point Enhanced LP
Related Party Transaction [Line Items]
Investments in related party investment funds, at fair value	77.8	77.5
Related Party | Third Point Venture Offshore Fund I LP
Related Party Transaction [Line Items]
Investments in related party investment funds, at fair value	24.7	25
Related Party | Third Point Venture Offshore Fund II LP
Related Party Transaction [Line Items]
Investments in related party investment funds, at fair value	$ 3.1	$ 3.1

Related party transactions - Su

Related party transactions - Summary of related party fees (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Management, advisory and performance fees to related parties	$ 2.1	$ 1.7
Management and advisory fees
Related Party Transaction [Line Items]
Management, advisory and performance fees to related parties	1.7	1.7
Performance fees
Related Party Transaction [Line Items]
Management, advisory and performance fees to related parties	$ 0.4	$ 0

Commitments and contingencies -

Commitments and contingencies - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended		10 Months Ended
	Feb. 26, 2023	Mar. 07, 2022	Feb. 26, 2021	Sep. 16, 2020	Mar. 31, 2024	Mar. 31, 2023	Nov. 05, 2023	Dec. 31, 2023
Other Commitments [Line Items]
Liability-classified capital instruments					$ 83.2			$ 67.3
Dividends paid to preference shareholders					4	$ 4
Private warrants exercised (in shares)							5,418,434
Settlement of contingent value rights					0	38.5
Operating lease expense					2.2	2.5
Series A preference shares
Other Commitments [Line Items]
Liability-classified capital instruments					41.5			37.6
Merger warrants
Other Commitments [Line Items]
Liability-classified capital instruments					41.7			$ 29.7
CVRs
Other Commitments [Line Items]
Settlement of contingent value rights	$ 38.5
Liability-classified capital instruments | Series A preference shares
Other Commitments [Line Items]
Gains (losses) from the change in fair value					(3.9)	5.3
Liability-classified capital instruments | Merger warrants
Other Commitments [Line Items]
Gains (losses) from the change in fair value					$ (12)	(16)
Liability-classified capital instruments | Private warrants
Other Commitments [Line Items]
Gains (losses) from the change in fair value						$ (4.3)
Sirius Group | Series A preference shares
Other Commitments [Line Items]
Par value (in dollars per share)			$ 0.10
Issuance of SiriusPoint common shares (in shares)			11,720,987
Sirius Group | Merger warrants
Other Commitments [Line Items]
Number of shares in which the warrants can be converted (in shares)					21,009,324
Sirius Group | Series A preference shares
Other Commitments [Line Items]
Dividends paid to preference shareholders					$ 0
Player's Health
Other Commitments [Line Items]
Amount lent under note agreement		$ 8
Notes receivable, interest rate		6%
Related Party
Other Commitments [Line Items]
Related party interest rate				8%
Amount drawn					$ 0
Related Party | Loan commitment
Other Commitments [Line Items]
Maximum commitment				$ 18

Commitments and contingencies_2

Commitments and contingencies - Lease balances (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Operating lease right-of-use assets	$ 24.2	$ 25.6
Total lease liability	$ 26.6	$ 28.4
Weighted average lease term (years)	3 years 10 months 24 days	4 years 1 month 6 days
Weighted average discount rate	2.90%	2.90%
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities

Commitments and contingencies_3

Commitments and contingencies - Future minimum rental commitments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2024	$ 4.9
2025	5.8
2026	5
2027	4.1
2028 and thereafter	9.2
Total future annual minimum rental payments	29
Less: present value discount	(2.4)
Total lease liability	$ 26.6	$ 28.4

Subsequent event (Details)

Subsequent event (Details) $ in Millions	Apr. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Mar. 02, 2023	Sep. 30, 2022 USD ($)
Subsequent Event [Line Items]
Loss reserves		$ 905.6		$ 1,300
Aggregate limit, percentage of booked reserves			1.30
Subsequent event
Subsequent Event [Line Items]
Loss reserves	$ 400
Aggregate limit, percentage of booked reserves	1.50