Alterra Capital 8-K Alterra Capital Reports Third Quarter 2011 Results

Exhibit 99.2

ALTERRA CAPITAL HOLDINGS LIMITED

Investor Financial Supplement

Third Quarter 2011

(Unaudited)

This supplement is for information purposes only. It should be read in conjunction with documents filed by Alterra Capital Holdings Limited with the U.S. Securities and Exchange Commission pursuant to the Securities Exchange Act 1934.

Alterra Capital Holdings Limited

Investors:

Susan Spivak Bernstein, +1-212-898-6640

or

Media:

Kekst and Company

Peter Hill or Melissa Sheer, +1-212-521-4800

ALTERRA CAPITAL HOLDINGS LIMITED

Cautionary note regarding forward-looking information

This financial supplement may include forward-looking statements that reflect Alterra’s current views with respect to future events and financial performance. Statements that include the words “expect,” “intend,” “plan,” “believe,” “project,” “anticipate,” “will,” “may” and similar statements of a future or forward-looking nature identify forward-looking statements. All forward-looking statements address matters that involve risks and uncertainties. Accordingly, there are important factors that could cause actual results to differ materially from those indicated in such statements and you should not place undue reliance on any such statements.

These factors include, but are not limited to, the following: (1) the adequacy of loss reserves and the need to adjust such reserves as claims develop over time; (2) the failure of any of the loss limitation methods employed; (3) the effect of cyclical trends, including with respect to demand and pricing in the insurance and reinsurance markets; (4) changes in general economic conditions, including changes in capital and credit markets; (5) any lowering or loss of financial ratings; (6) the occurrence of natural or man-made catastrophic events with a frequency or severity exceeding expectations; (7) actions by competitors, including consolidation; (8) the effects of emerging claims and coverage issues; (9) the loss of business provided to Alterra by its major brokers; (10) the effect on Alterra’s investment portfolio of changing financial market conditions including inflation, interest rates, liquidity and other factors; (11) tax and regulatory changes and conditions; (12) retention of key personnel; and (13) the integration of new business ventures Alterra may enter into; as well as management’s response to any of the aforementioned factors.

The foregoing review of important factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included herein and elsewhere, including the Risk Factors included in Alterra’s most recent reports on Form 10-K and Form 10-Q and other documents on file with the U.S. Securities and Exchange Commission. Any forward-looking statements made in this financial supplement are qualified by these cautionary statements, and there can be no assurance that the actual results or developments anticipated by Alterra will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, Alterra or its business or operations. Alterra undertakes no obligation to update publicly or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

2

ALTERRA CAPITAL HOLDINGS LIMITED

FINANCIAL SUPPLEMENT TABLE OF CONTENTS

	Page
Financial Highlights		4
Consolidated Balance Sheets		5
Consolidated Statements of Operations - Quarterly		6
Consolidated Statements of Operations - Year to date		7
Segment Data and Ratios - Quarterly		8
Gross Premiums Written by Line of Business - Quarterly		16
Segment Data and Ratios - Year to date		18
Gross Premiums Written by Line of Business - Year to date		25
Investment Portfolio		26
Shareholder Return Analysis		29
Earnings Per Share Information		30
Operating Income Reconciliation		31
Book Value per Share		32
Regulation G		33
Reclassified Historical Segment Information		34
Pro forma Consolidated Statements of Income		38

ALTERRA CAPITAL HOLDINGS LIMITED

FINANCIAL HIGHLIGHTS

(Expressed in thousands of United States Dollars, except per share and share amounts)

	For The Quarters Ended						For The Nine Months Ended
	Sept. 30, 2011			Sept. 30, 2010			Sept. 30, 2011			Sept. 30, 2010			Previous Year Quarter  Change			Previous Year to Date Change
HIGHLIGHTS
Net income	$	48,386		$	82,837		$	34,334		$	222,665			(41.6	%)		(84.6	%)
Net operating income [a]		50,082			76,041			64,915			175,496			(34.1	%)		(63.0	%)
Operating cashflow		126,770			(4,768	)		275,475			169,013			n/m			63.0	%
Gross premiums written		386,328			325,213			1,578,083			1,095,333			18.8	%		44.1	%
Net premiums earned		347,042			342,432			1,075,870			829,932			1.3	%		29.6	%
Total assets		10,472,330			10,118,934			10,472,330			10,118,934			3.5	%		3.5	%
Total shareholders’ equity		2,844,738			3,036,537			2,844,738			3,036,537			(6.3	%)		(6.3	%)
PER SHARE
Basic earnings per share
Net income	$	0.46		$	0.71		$	0.32		$	2.52
Net operating income [a]		0.48			0.65			0.61			1.99
Diluted earnings per share
Net income	$	0.46		$	0.70		$	0.32		$	2.50
Net operating income [a]		0.47			0.64			0.61			1.97
Weighted average shares outstanding - basic		104,830,300			117,200,505			105,866,771			88,253,609
Weighted average shares outstanding - diluted		105,665,282			117,957,942			107,092,882			89,001,515
Book value per common share [b]	$	27.27		$	26.20		$	27.27		$	26.20			4.1	%		4.1	%
Diluted book value per share (treasury stock method) [b]		27.18			25.88			27.18			25.88			5.0	%		5.0	%
Diluted tangible book value per share (treasury stock method) [b]		26.64			25.37			26.64			25.37			5.0	%		5.0	%
RATIOS
Annualized return on average shareholders’ equity [c]		6.9	%		11.1	%		1.6	%		12.9	%
Annualized net operating return on average shareholders’ equity [c]		7.1	%		10.2	%		3.1	%		10.2	%
Loss ratio [d]		57.3	%		56.0	%		66.5	%		57.5	%
Acquisition cost ratio [d]		17.7	%		17.8	%		18.3	%		16.1	%
General and administrative expense ratio [d]		12.7	%		12.2	%		13.7	%		12.4	%
Combined ratio [d]		87.7	%		86.0	%		98.4	%		86.1	%

[a] Net operating income represents net income excluding, as applicable, after-tax net realized and unrealized gains and losses on non-hedge fund investments, after-tax net foreign exchange gains or losses, and after-tax merger and acquisition expenses.

[b] For detailed calculations see page 32.

[c] For detailed calculations see page 29.

[d] For property and casualty business only.

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ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED BALANCE SHEETS

(Expressed in thousands of United States Dollars, except per share and share amounts)

	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010			Sept. 30, 2010
	(Unaudited)			(Unaudited)			(Unaudited)						(Unaudited)
ASSETS
Cash and cash equivalents	$	869,975		$	987,057		$	1,001,051		$	905,606		$	925,752
Fixed maturities, trading at fair value		227,753			218,481			214,807			244,872			243,158
Fixed maturities, available for sale at fair value		5,662,869			5,403,312			5,290,684			5,392,643			5,425,955
Fixed maturities, held to maturity at amortized cost		926,916			993,691			983,207			940,104			954,623
Other investments, at fair value		311,633			350,193			357,655			378,128			411,275
Accrued interest income		71,038			70,777			69,497			75,414			73,622
Premiums receivable		777,980			870,287			809,483			588,537			664,603
Losses and benefits recoverable from reinsurers		1,079,035			1,058,724			1,053,223			956,115			976,819
Deferred acquisition costs		166,353			171,517			149,197			111,901			106,728
Prepaid reinsurance premiums		214,132			215,392			176,918			149,252			173,140
Trades pending settlement		34,158			9,168			—			32,393			24,364
Goodwill and intangible assets		56,652			58,094			58,585			59,076			60,670
Other assets		73,836			90,671			86,072			83,247			78,225
Total assets	$	10,472,330		$	10,497,364		$	10,250,379		$	9,917,288		$	10,118,934
LIABILITIES
Property and casualty losses	$	4,205,057		$	4,230,290		$	4,185,230		$	3,906,134		$	3,847,366
Life and annuity benefits		1,230,344			1,317,527			1,316,287			1,275,580			1,299,190
Deposit liabilities		147,493			147,428			147,424			147,612			147,212
Funds withheld from reinsurers		124,631			122,705			122,072			121,107			119,859
Unearned property and casualty premiums		1,149,108			1,203,024			1,065,160			905,487			1,015,831
Reinsurance balances payable		178,560			137,910			127,299			102,942			122,184
Accounts payable and accrued expenses		110,527			104,917			103,376			99,680			90,282
Trades pending settlement		41,383			—			19,855			—			—
Senior notes		440,489			440,482			440,482			440,476			440,473
Total liabilities		7,627,592			7,704,283			7,527,185			6,999,018			7,082,397
SHAREHOLDERS’ EQUITY
Common shares (par value $1.00) 104,323,873 shares issued and outstanding		104,324			105,795			105,734			110,963			115,899
Additional paid-in capital		1,890,763			1,911,979			1,905,144			2,026,045			2,113,732
Accumulated other comprehensive income		173,025			132,218			89,233			98,946			190,325
Retained earnings		676,626			643,089			623,083			682,316			616,581
Total shareholders’ equity		2,844,738			2,793,081			2,723,194			2,918,270			3,036,537
Total liabilities and shareholders’ equity	$	10,472,330		$	10,497,364		$	10,250,379		$	9,917,288		$	10,118,934
Book value per share	$	27.27		$	26.40		$	25.76		$	26.30		$	26.20
Diluted book value per share (treasury stock method)	$	27.18		$	25.98		$	25.34		$	25.99		$	25.88
Diluted tangible book value per share (treasury stock method) [a]	$	26.64		$	25.44		$	24.79		$	25.46		$	25.37
Debt-to-capital ratio [b]		13.4	%		13.6	%		13.9	%		13.1	%		12.7	%

[a] Non-GAAP financial measure. For detailed calculations see page 32.

[b] Calculated as debt, being senior notes, divided by shareholders’ equity plus debt.

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ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - QUARTERLY (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010			Sept. 30, 2010			Sept. 30, 2009
REVENUES
Gross premiums written	$	386,328		$	563,907		$	627,848		$	315,398		$	325,213		$	265,886
Reinsurance premiums ceded		(90,891	)		(136,626	)		(137,357	)		(77,617	)		(60,611	)		(83,290	)
Net premiums written	$	295,437		$	427,281		$	490,491		$	237,781		$	264,602		$	182,596
Earned premiums	$	452,931		$	443,008		$	489,262		$	445,683		$	436,244		$	329,869
Earned premiums ceded		(105,889	)		(94,067	)		(109,375	)		(103,129	)		(93,812	)		(121,853	)
Net premiums earned		347,042			348,941			379,887			342,554			342,432			208,016
Net investment income		60,335			59,665			57,766			61,080			59,711			42,830
Net realized and unrealized (losses) gains on investments		(7,972	)		(5,774	)		(18,818	)		9,825			15,411			24,528
Total other-than-temporary impairment losses		(692	)		(187	)		(1,124	)		(3,918	)		(90	)		—
Portion of loss recognized in other comprehensive income (loss) before taxes		(169	)		(166	)		95			2,144			(61	)		(139	)
Net impairment losses recognized in earnings		(861	)		(353	)		(1,029	)		(1,774	)		(151	)		(139	)
Other income		1,473			591			1,315			2,862			1,327			819
Total revenues		400,017			403,070			419,121			414,547			418,730			276,054
LOSSES AND EXPENSES
Net losses and loss expenses		198,521			211,133			304,406			179,047			191,012			131,778
Claims and policy benefits		14,538			15,570			14,710			18,551			15,060			14,378
Acquisition costs		61,434			64,680			70,608			53,563			60,859			27,997
Interest expense		11,303			10,630			8,459			7,866			7,551			5,971
Net foreign exchange (gains) losses		(147	)		3,090			(878	)		(382	)		3,353			406
Merger and acquisition expenses		—			—			—			500			550			(41,350	)
General and administrative expenses		61,555			69,659			71,203			76,759			56,650			40,372
Total losses and expenses		347,204			374,762			468,508			335,904			335,035			179,552
INCOME (LOSS) BEFORE TAXES		52,813			28,308			(49,387	)		78,643			83,695			96,502
Income tax expense (benefit)		4,427			(4,327	)		(2,700	)		(1,027	)		858			1,176
NET INCOME (LOSS)		48,386			32,635			(46,687	)		79,670			82,837			95,326
Change in net unrealized gains and losses on fixed maturities, net of tax		61,540			42,820			(14,586	)		(87,633	)		74,383			95,794
Foreign currency translation adjustment		(20,733	)		165			4,873			(3,746	)		13,224			(4,462	)
COMPREHENSIVE INCOME (LOSS)	$	89,193		$	75,620		$	(56,400	)	$	(11,709	)	$	170,444		$	186,658
KEY RATIOS/PER SHARE DATA
Loss ratio [a]		57.3	%		60.7	%		80.2	%		52.5	%		56.0	%		63.4	%
Acquisition cost ratio [b]		17.7	%		18.5	%		18.6	%		15.7	%		17.8	%		13.4	%
General and administrative expense ratio [c]		12.7	%		14.5	%		13.8	%		16.6	%		12.2	%		14.1	%
Combined ratio [d]		87.7	%		93.7	%		112.5	%		84.8	%		86.0	%		90.9	%
Net income (loss) per share	$	0.46		$	0.31		$	(0.44	)	$	0.70		$	0.71		$	1.67
Net income (loss) per diluted share	$	0.46		$	0.30		$	(0.44	)	$	0.69		$	0.70		$	1.64
Net operating income (loss) per share - diluted [e]	$	0.47		$	0.37		$	(0.23	)	$	0.66		$	0.64		$	0.92
Annualized ROAE [f]		6.9	%		4.7	%		(6.6	%)		10.7	%		11.1	%		26.2	%
Annualized net operating ROAE [f]		7.1	%		5.7	%		(3.5	%)		10.2	%		10.2	%		14.8	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned for the property & casualty business.

[b] The acquisition cost ratio is calculated by dividing acquisition costs by net premiums earned for the property & casualty business.

[c] The general and administrative expense ratio is calculated by dividing general and administrative expenses by net premiums earned for the property & casualty business.

[d] The combined ratio is calculated by dividing the sum of net losses and loss expenses, acquistion costs and general and administrative expenses by net premiums earned for the property & casualty business.

[e] Non-GAAP financial measure. See page 31 for calculation of net operating income per share - diluted.

[f] Non-GAAP financial measure. See page 29 for calculation of annualized return on average shareholders’ equity (ROAE) and annualized net operating ROAE.

Results for Harbor Point Limited (“Harbor Point”) are included from May 12, 2010.

Percentage totals may not add due to rounding.

6

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - YEAR TO DATE AND PRIOR YEARS (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	NINE MONTHS ENDED									YEAR ENDED
	Sept. 30, 2011			Sept. 30, 2010 [g]			Sept. 30, 2009			Dec. 31, 2010 [g]			Dec. 31, 2009
REVENUES
Gross premiums written	$	1,578,083		$	1,095,333		$	1,096,668		$	1,410,731		$	1,375,001
Reinsurance premiums ceded		(364,874	)		(293,546	)		(377,338	)		(371,163	)		(480,481	)
Net premiums written	$	1,213,209		$	801,787		$	719,330		$	1,039,568		$	894,520
Earned premiums	$	1,385,201		$	1,132,964		$	993,871		$	1,578,647		$	1,318,949
Earned premiums ceded		(309,331	)		(303,032	)		(366,788	)		(406,161	)		(484,593	)
Net premiums earned		1,075,870			829,932			627,083			1,172,486			834,356
Net investment income		177,766			161,378			125,073			222,458			169,741
Net realized and unrealized (losses) gains on investments		(32,564	)		7,047			64,440			16,872			81,765
Total other-than-temporary impairment losses		(2,003	)		(1,955	)		(5,190	)		(5,873	)		(5,315	)
Portion of loss recognized in other comprehensive income (loss) before taxes		(240	)		1,084			3,037			3,228			2,237
Net impairment losses recognized in earnings		(2,243	)		(871	)		(2,153	)		(2,645	)		(3,078	)
Net realized gain on retirement of senior notes		—			—			—			—			111
Other income		3,379			1,946			3,099			4,808			2,903
Total revenues		1,222,208			999,432			817,542			1,413,979			1,085,798
LOSSES AND EXPENSES
Net losses and loss expenses		714,060			475,794			378,729			654,841			493,599
Claims and policy benefits		44,818			46,662			84,117			65,213			101,093
Acquisition costs		196,722			133,901			73,686			187,464			96,874
Interest expense		30,392			20,409			14,654			28,275			21,339
Net foreign exchange losses (gains)		2,065			267			(6,474	)		(115	)		(5,772	)
Merger and acquisition expenses		—			(49,276	)		(31,342	)		(48,776	)		(31,566	)
General and administrative expenses		202,417			143,827			115,537			220,586			153,995
Total losses and expenses		1,190,474			771,584			628,907			1,107,488			829,562
INCOME BEFORE TAXES		31,734			227,848			188,635			306,491			256,236
Income tax (benefit) expense		(2,600	)		5,183			5,012			4,156			10,021
NET INCOME		34,334			222,665			183,623			302,335			246,215
Change in net unrealized gains and losses on fixed maturities, net of tax		89,774			169,039			66,629			81,406			50,544
Foreign currency translation adjustment		(15,695	)		(4,145	)		20,372			(7,891	)		20,286
COMPREHENSIVE INCOME	$	108,413		$	387,559		$	270,624		$	375,850		$	317,045
KEY RATIOS/PER SHARE DATA
Loss ratio [a]		66.5	%		57.5	%		64.7	%		56.1	%		62.4	%
Acquisition cost ratio [b]		18.3	%		16.1	%		12.4	%		16.0	%		12.1	%
General and administrative expense ratio [c]		13.7	%		12.4	%		13.4	%		13.6	%		13.6	%
Combined ratio [d]		98.4	%		86.1	%		90.5	%		85.7	%		88.1	%
Net income per share - basic	$	0.32		$	2.52		$	3.22		$	3.19		$	4.32
Net income per share - diluted	$	0.32		$	2.50		$	3.18		$	3.17		$	4.26
Net operating income per share - diluted [e]	$	0.61		$	1.97		$	2.57		$	2.64		$	3.62
Annualized ROAE [f]		1.6	%		12.9	%		18.2	%		12.3	%		17.6	%
Annualized Net Operating ROAE [f]		3.1	%		10.2	%		14.7	%		10.2	%		14.9	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned for the property & casualty business.

[b] The acquisition cost ratio is calculated by dividing acquisition costs by net premiums earned for the property & casualty business.

[c] The general and administrative expense ratio is calculated by dividing general and administrative expenses by net premiums earned for the property & casualty business.

[d] The combined ratio is calculated by dividing the sum of net losses and loss expenses, acquistion costs and general and administrative expenses by net premiums earned for the property & casualty business.

[e] Non-GAAP financial measure. See page 31 for calculation of net operating income per share - diluted.

[f] Non-GAAP financial measure. See page 29 for calculation of annualized return on average shareholders’ equity (ROAE) and annualized net operating ROAE.

[g] Includes the results for Harbor Point from May 12, 2010.

Percentage totals may not add due to rounding.

7

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–THREE MONTHS ENDED SEPTEMBER 30, 2011 (Unaudited)

(Expressed in thousands of United States Dollars)

	Property & Casualty															Life & Annuity			Corporate			Consolidated
	Insurance			Reinsurance			U.S. Specialty			Alterra  at Lloyd’s			Total			Reinsurance
Gross premiums written	$	85,996		$	156,784		$	72,159		$	70,567		$	385,506		$	822		$	—		$	386,328
Reinsurance premiums ceded		(43,195	)		(15,874	)		(25,009	)		(6,723	)		(90,801	)		(90	)		—			(90,891	)
Net premiums written	$	42,801		$	140,910		$	47,150		$	63,844		$	294,705		$	732		$	—		$	295,437
Earned premiums	$	101,355		$	217,763		$	75,391		$	57,600		$	452,109		$	822		$	—		$	452,931
Earned premiums ceded		(51,578	)		(18,489	)		(24,882	)		(10,850	)		(105,799	)		(90	)		—			(105,889	)
Net premiums earned		49,777			199,274			50,509			46,750			346,310			732			—			347,042
Net losses and loss expenses		(23,649	)		(113,757	)		(33,641	)		(27,474	)		(198,521	)		—			—			(198,521	)
Claims and policy benefits		—			—			—			—			—			(14,538	)		—			(14,538	)
Acquisition costs		609			(44,298	)		(9,530	)		(8,070	)		(61,289	)		(145	)		—			(61,434	)
General and administrative expenses		(8,861	)		(17,673	)		(8,066	)		(9,235	)		(43,835	)		(145	)		—			(43,980	)
Other income (loss)		58			777			—			(27	)		808			(8	)		—			800
Underwriting income (loss)		17,934			24,323			(728	)		1,944			43,473			n/a			—			n/a
Net investment income																	12,131			48,204			60,335
Net realized and unrealized losses on investments																	(6,407	)		(1,565	)		(7,972	)
Net impairment losses recognized in earnings																				(861	)		(861	)
Corporate other income																				673			673
Interest expense																				(11,303	)		(11,303	)
Net foreign exchange gains																				147			147
Corporate general and administrative expenses																				(17,575	)		(17,575	)
(Loss) income before taxes																$	(8,380	)	$	17,720		$	52,813
Loss ratio [a]		47.5	%		57.1	%		66.6	%		58.8	%		57.3	%
Acquisition cost ratio [b]		(1.2	%)		22.2	%		18.9	%		17.3	%		17.7	%
General and administrative expense ratio [c]		17.8	%		8.9	%		16.0	%		19.8	%		12.7	%
Combined ratio [d]		64.1	%		88.2	%		101.4	%		95.8	%		87.7	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned for the property & casualty business.

[b] The acquisition cost ratio is calculated by dividing acquisition costs by net premiums earned for the property & casualty business.

[c] The general and administrative expense ratio is calculated by dividing general and administrative expenses by net premiums earned for the property & casualty business.

[d] The combined ratio is calculated by dividing the sum of net losses and loss expenses, acquisition costs and general and administrative expenses by net premiums earned for the property & casualty business.

Percentage totals may not add due to rounding.

8

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED UNDERWRITING RATIOS - THREE MONTHS ENDED SEPTEMBER 30, 2011 (Unaudited)

	Property & Casualty
	Insurance			Reinsurance			U.S. Specialty			Alterra  at Lloyd’s			Total
UNDERWRITING RATIOS
Loss ratio		47.5	%		57.1	%		66.6	%		58.8	%		57.3	%
Acquisition cost ratio		(1.2	%)		22.2	%		18.9	%		17.3	%		17.7	%
General and administrative expense ratio		17.8	%		8.9	%		16.0	%		19.8	%		12.7	%
Combined ratio		64.1	%		88.2	%		101.4	%		95.8	%		87.7	%
EFFECT OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT FAVORABLE / (UNFAVORABLE)
Loss ratio [a]		39.2	%		5.8	%		(2.8	%)		4.1	%		9.1	%
NET OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT UNDERWRITING RATIOS
Loss ratio		86.7	%		62.9	%		63.8	%		62.9	%		66.5	%
Acquisition cost ratio		(1.2	%)		22.2	%		18.9	%		17.3	%		17.7	%
General and administrative expense ratio		17.8	%		8.9	%		16.0	%		19.8	%		12.7	%
Combined ratio		103.3	%		94.0	%		98.6	%		99.9	%		96.8	%

[a] Prior accident year reserve development excludes changes in reserves resulting from changes in premium estimates on prior years’ contracts.

CONSOLIDATED UNDERWRITING RATIOS - THREE MONTHS ENDED SEPTEMBER 30, 2010 (Unaudited)

	Property & Casualty
	Insurance [b]			Reinsurance			U.S. Specialty [b]			Alterra  at Lloyd’s			Total
UNDERWRITING RATIOS
Loss ratio		44.6	%		59.4	%		62.0	%		48.1	%		56.0	%
Acquisition cost ratio		2.3	%		22.8	%		14.3	%		20.7	%		17.8	%
General and administrative expense ratio		12.9	%		8.9	%		18.4	%		21.6	%		12.2	%
Combined ratio		59.8	%		91.1	%		94.7	%		90.4	%		86.0	%
EFFECT OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT FAVORABLE / (UNFAVORABLE)
Loss ratio [a]		29.9	%		7.2	%		0.0	%		12.1	%		10.6	%
NET OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT UNDERWRITING RATIOS
Loss ratio		74.5	%		66.6	%		62.0	%		46.6	%		66.6	%
Acquisition cost ratio		2.3	%		22.8	%		14.3	%		20.7	%		17.8	%
General and administrative expense ratio		12.9	%		8.9	%		18.4	%		21.6	%		12.2	%
Combined ratio		89.7	%		98.3	%		94.7	%		102.5	%		96.6	%

[a] Prior accident year reserve development excludes changes in reserves resulting from changes in premium estimates on prior years’ contracts.

[b] Insurance and U.S. Specialty segment amounts for the comparative 2010 period have been reclassified to conform with the current period’s presentation.

Percentage totals may not add due to rounding.

9

ALTERRA CAPITAL HOLDINGS LIMITED

INSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010  [a]			Sept. 30, 2010  [a]			Sept. 30, 2009  [a]
Gross premiums written	$	85,996		$	141,255		$	71,272		$	113,236		$	77,944		$	90,430
Reinsurance premiums ceded		(43,195	)		(56,002	)		(43,246	)		(56,728	)		(36,875	)		(43,388	)
Net premiums written	$	42,801		$	85,253		$	28,026		$	56,508		$	41,069		$	47,042
Earned premiums	$	101,355		$	97,296		$	98,944		$	106,169		$	102,640		$	108,776
Earned premiums ceded		(51,578	)		(44,338	)		(44,730	)		(43,847	)		(42,796	)		(56,337	)
Net premiums earned		49,777			52,958			54,214			62,322			59,844			52,439
Net losses and loss expenses		(23,649	)		(28,992	)		(34,664	)		(35,687	)		(26,679	)		(34,515	)
Acquisition costs		609			361			(184	)		(1,765	)		(1,382	)		(331	)
General and administrative expenses		(8,861	)		(8,859	)		(9,825	)		(11,812	)		(7,717	)		(8,114	)
Other income		58			139			812			68			1,108			143
Underwriting income	$	17,934		$	15,607		$	10,353		$	13,126		$	25,174		$	9,622
Loss ratio		47.5	%		54.7	%		63.9	%		57.3	%		44.6	%		65.8	%
Acquisition cost ratio		(1.2	%)		(0.7	%)		0.3	%		2.8	%		2.3	%		0.6	%
General and administrative expense ratio		17.8	%		16.7	%		18.1	%		19.0	%		12.9	%		15.5	%
Combined ratio		64.1	%		70.8	%		82.4	%		79.0	%		59.8	%		81.9	%

[a] Insurance and U.S. Specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation. See page 34 for additional information.

10

ALTERRA CAPITAL HOLDINGS LIMITED

REINSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010			Sept. 30, 2010			Sept. 30, 2009
Gross premiums written	$	156,784		$	248,754		$	375,020		$	110,620		$	124,004		$	94,118
Reinsurance premiums ceded		(15,874	)		(28,247	)		(37,317	)		(2,908	)		(2,524	)		(11,106	)
Net premiums written	$	140,910		$	220,507		$	337,703		$	107,712		$	121,480		$	83,012
Earned premiums	$	217,763		$	209,212		$	249,901		$	215,261		$	213,510		$	128,458
Earned premiums ceded		(18,489	)		(12,305	)		(20,195	)		(21,082	)		(15,533	)		(25,367	)
Net premiums earned		199,274			196,907			229,706			194,179			197,977			103,091
Net losses and loss expenses		(113,757	)		(125,592	)		(186,885	)		(97,639	)		(117,671	)		(68,728	)
Acquisition costs		(44,298	)		(44,366	)		(49,143	)		(38,406	)		(45,069	)		(20,299	)
General and administrative expenses		(17,673	)		(22,937	)		(23,258	)		(24,714	)		(17,580	)		(8,857	)
Other income		777			548			—			(216	)		61			—
Underwriting income (loss)	$	24,323		$	4,560		$	(29,580	)	$	33,204		$	17,718		$	5,207
Loss ratio		57.1	%		63.8	%		81.4	%		50.3	%		59.4	%		66.7	%
Acquisition cost ratio		22.2	%		22.5	%		21.4	%		19.8	%		22.8	%		19.7	%
General and administrative expense ratio		8.9	%		11.6	%		10.1	%		12.7	%		8.9	%		8.5	%
Combined ratio		88.2	%		98.0	%		112.9	%		82.8	%		91.1	%		94.9	%

11

ALTERRA CAPITAL HOLDINGS LIMITED

PRO FORMA ALTERRA REINSURANCE SEGMENT SELECTED FINANCIAL INFORMATION [a] (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Dec. 31, 2010			Sept. 30, 2010			June 30, 2010			Mar. 31, 2010			Dec. 31, 2009			Sept. 30, 2009			June 30, 2009			Mar. 31, 2009
Gross premiums written	$	110,620		$	124,004		$	197,146		$	460,618		$	125,447		$	210,882		$	262,938		$	461,141
Net premiums earned		194,179			197,977			226,291			215,050			230,516			238,953			221,120			220,103
Net losses and loss expenses		97,639			117,671			136,158			129,727			108,941			113,625			118,613			115,706
Acquisition costs		38,406			45,069			47,179			42,689			46,708			50,167			42,586			43,280
General and administrative expenses		24,714			17,580			16,527			16,824			23,680			19,726			18,520			19,201
Loss ratio		50.3	%		59.4	%		60.2	%		60.3	%		47.3	%		47.6	%		53.6	%		52.6	%
Acquisition cost ratio		19.8	%		22.8	%		20.8	%		19.9	%		20.3	%		21.0	%		19.3	%		19.7	%
General and administrative expense ratio		12.7	%		8.9	%		7.3	%		7.8	%		10.3	%		8.3	%		8.4	%		8.7	%
Combined ratio		82.8	%		91.1	%		88.3	%		88.0	%		77.8	%		76.8	%		81.3	%		81.0	%

[a] This information is based on historical Alterra reinsurance segment financial information adjusted to include Harbor Point historical financial information as though the amalgamation with Harbor Point had occurred on January 1, 2009. The financial information also includes adjustments to eliminate any intercompany transactions and to reflect the amortization of certain acquisition accounting fair value adjustments.

The pro forma information is provided for informational purposes only. The pro forma information does not necessarily represent results that would have occurred if the amalgamation had occurred on January 1, 2009, nor is it necessarily indicative of future results.

12

ALTERRA CAPITAL HOLDINGS LIMITED

U.S. SPECIALTY SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010  [a]			Sept. 30, 2010  [a]			Sept. 30, 2009  [a]
Gross premiums written	$	72,159		$	99,448		$	70,388		$	65,625		$	64,198		$	60,123
Reinsurance premiums ceded		(25,009	)		(27,358	)		(33,595	)		(15,956	)		(18,713	)		(24,755	)
Net premiums written	$	47,150		$	72,090		$	36,793		$	49,669		$	45,485		$	35,368
Earned premiums	$	75,391		$	73,840		$	73,177		$	74,683		$	73,337		$	63,360
Earned premiums ceded		(24,882	)		(22,783	)		(23,850	)		(26,140	)		(26,071	)		(35,551	)
Net premiums earned		50,509			51,057			49,327			48,543			47,266			27,809
Net losses and loss expenses		(33,641	)		(32,709	)		(31,375	)		(31,878	)		(29,295	)		(18,507	)
Acquisition costs		(9,530	)		(9,644	)		(8,066	)		(8,618	)		(6,763	)		(1,964	)
General and administrative expenses		(8,066	)		(9,289	)		(9,397	)		(7,552	)		(8,693	)		(6,971	)
Underwriting (loss) income	$	(728	)	$	(585	)	$	489		$	495		$	2,515		$	367
Loss ratio		66.6	%		64.1	%		63.6	%		65.7	%		62.0	%		66.6	%
Acquisition cost ratio		18.9	%		18.9	%		16.4	%		17.8	%		14.3	%		7.1	%
General and administrative expense ratio		16.0	%		18.2	%		19.1	%		15.6	%		18.4	%		25.1	%
Combined ratio		101.4	%		101.1	%		99.0	%		99.0	%		94.7	%		98.7	%

[a] Insurance and U.S. Specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation. See page 34 for additional information.

13

ALTERRA CAPITAL HOLDINGS LIMITED

ALTERRA AT LLOYD’S SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010			Sept. 30, 2010			Sept. 30, 2009
Gross premiums written	$	70,567		$	73,520		$	110,733		$	23,980		$	57,734		$	21,087
Reinsurance premiums ceded		(6,723	)		(24,918	)		(23,179	)		(1,859	)		(2,397	)		(4,015	)
Net premiums written	$	63,844		$	48,602		$	87,554		$	22,121		$	55,337		$	17,072
Earned premiums	$	57,600		$	61,730		$	66,805		$	47,633		$	45,424		$	29,147
Earned premiums ceded		(10,850	)		(14,540	)		(20,580	)		(11,894	)		(9,310	)		(4,572	)
Net premiums earned		46,750			47,190			46,225			35,739			36,114			24,575
Net losses and loss expenses		(27,474	)		(23,840	)		(51,482	)		(13,843	)		(17,367	)		(10,028	)
Acquisition costs		(8,070	)		(10,909	)		(13,056	)		(4,853	)		(7,474	)		(5,250	)
General and administrative expenses		(9,235	)		(9,536	)		(9,723	)		(12,186	)		(7,806	)		(5,423	)
Other income (loss)		(27	)		165			215			2,006			177			(33	)
Underwriting income (loss)	$	1,944		$	3,070		$	(27,821	)	$	6,863		$	3,644		$	3,841
Loss ratio		58.8	%		50.5	%		111.4	%		38.7	%		48.1	%		40.8	%
Acquisition cost ratio		17.3	%		23.1	%		28.2	%		13.6	%		20.7	%		21.4	%
General and administrative expense ratio		19.8	%		20.2	%		21.0	%		34.1	%		21.6	%		22.0	%
Combined ratio		95.8	%		93.8	%		160.7	%		86.4	%		90.4	%		84.2	%

14

ALTERRA CAPITAL HOLDINGS LIMITED

LIFE AND ANNUITY REINSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010			Sept. 30, 2010			Sept. 30, 2009
Gross premiums written	$	822		$	930		$	435		$	1,937		$	1,333		$	128
Reinsurance premiums ceded		(90	)		(101	)		(20	)		(166	)		(102	)		(26	)
Net premiums written	$	732		$	829		$	415		$	1,771		$	1,231		$	102
Earned premiums	$	822		$	930		$	435		$	1,937		$	1,333		$	128
Earned premiums ceded		(90	)		(101	)		(20	)		(166	)		(102	)		(26	)
Net premiums earned		732			829			415			1,771			1,231			102
Net investment income		12,131			12,545			12,343			12,084			12,182			13,143
Net realized and unrealized (losses) gains on investments		(6,407	)		(1,299	)		2,807			3,981			3,321			11,932
Other income (loss)		(8	)		(23	)		—			357			(43	)		—
Claims and policy benefits		(14,538	)		(15,570	)		(14,710	)		(18,551	)		(15,060	)		(14,378	)
Acquisition costs		(145	)		(122	)		(159	)		79			(171	)		(153	)
General and administrative expenses		(145	)		(259	)		(177	)		(1,088	)		(577	)		(829	)
(Loss) income before taxes	$	(8,380	)	$	(3,899	)	$	519		$	(1,367	)	$	883		$	9,817

15

ALTERRA CAPITAL HOLDINGS LIMITED

SEGMENT GROSS PREMIUMS WRITTEN BY LINE OF BUSINESS (Unaudited)

(Expressed in thousands of United States Dollars)

		FOR THE QUARTERS ENDED
		Sept. 30, 2011			June 30, 2011			Mar. 31, 2011			Dec. 31, 2010[a]			Sept. 30, 2010[a]			Sept 30, 2009[a]
Property & Casualty:
Insurance:
Aviation	S	$	6,736		$	3,814		$	1,416		$	22,677		$	8,247		$	13,495
Excess Liability	L		24,165			41,390			27,387			27,361			21,579			28,380
Professional Liability	L		39,489			66,017			26,796			51,199			37,151			39,146
Property	S		15,606			30,034			15,673			11,999			10,967			9,409
			85,996			141,255			71,272			113,236			77,944			90,430
Reinsurance [b]:
Agriculture	S		998			8,713			20,785			(1,406	)		(2,665	)		(95	)
Auto	S		8,994			55,105			15,160			22,585			10,251			—
Aviation	S		14,670			80			904			2,596			15,313			10,477
Credit/ Surety	S		7,116			1,556			24,426			1,118			2,569			—
General Casualty	L		22,570			22,045			16,247			17,658			18,505			7,279
Marine & Energy	S		4,131			(619	)		17,093			(1,549	)		8,826			5,987
Medical Malpractice	L		6,867			11,223			17,582			19,554			(3,131	)		2,567
Other	S		1,112			447			1,759			520			1,183			—
Professional Liability	L		40,075			39,462			59,684			28,538			37,965			20,992
Property	S		44,715			106,168			149,874			6,296			34,859			13,541
Whole Account	S/L		(1,946	)		268			35,070			426			(232	)		2,546
Workers’ Compensation	L		7,482			4,306			16,436			14,284			561			30,824
			156,784			248,754			375,020			110,620			124,004			94,118
U.S. Specialty:
General Liability	L		21,125			18,387			17,883			19,914			18,371			17,971
Marine	S		22,189			25,389			17,109			17,758			15,637			16,168
Professional Liability	L		4,419			4,894			4,355			(534	)		3,135			—
Property	S		24,426			50,778			31,041			28,487			27,055			25,984
			72,159			99,448			70,388			65,625			64,198			60,123
Alterra at Lloyd’s:
Accident & Health	S		9,523			8,380			13,544			5,570			5,919			3,692
Aviation	S		4,130			1,810			1,767			5,224			3,946			—
Financial Institutions	L		3,591			6,441			9,036			384			8,130			6,873
International Casualty	L		8,005			8,486			33,860			2,213			4,095			—
Professional Liability	L		440			10,466			7,922			4,204			4,330			5,284
Property	S		43,510			37,937			44,623			5,946			26,945			5,238
Surety	S		1,368			—			(19	)		439			4,369			—
			70,567			73,520			110,733			23,980			57,734			21,087
Aggregate Property & Casualty		$	385,506		$	562,977		$	627,413		$	313,461		$	323,880		$	265,758
Life & Annuity:
Annuity		$	449		$	271		$	336		$	1,129		$	—		$	—
Life			373			659			99			808			1,333			128
Aggregate Life & Annuity		$	822		$	930		$	435		$	1,937		$	1,333		$	128
Aggregate Property & Casualty and Life & Annuity		$	386,328		$	563,907		$	627,848		$	315,398		$	325,213		$	265,886

[a] Insurance and U.S. specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation.

[b] Includes the results for Harbor Point from May 12, 2010.

S = Short tail lines	$	208,251	$	329,726	$	372,690	$	128,473	$	173,305	$	105,169
L = Long tail lines		177,255		233,251		254,723		184,988		150,575		160,589
Aggregate Property & Casualty	$	385,506	$	562,977	$	627,413	$	313,461	$	323,880	$	265,758

16

ALTERRA CAPITAL HOLDINGS LIMITED

PRO FORMA ALTERRA REINSURANCE SEGMENT GROSS PREMIUMS WRITTEN BY LINE OF BUSINESS [a] (Unaudited)

(Expressed in thousands of United States Dollars)

Gross Premiums Written by Type of Risk:

		FOR THE QUARTERS ENDED
		Dec. 31, 2010			Sept. 30, 2010			June 30, 2010			Mar. 31, 2010		Dec. 31, 2009		Sept. 30, 2009			June 30, 2009			Mar. 31, 2009
Agriculture	S	$	(1,406	)	$	(2,665	)	$	(4,643	)	$	55,944	$	2,153	$	(96	)	$	(262	)	$	91,196
Auto	S		22,585			10,251			14,359			18,063		19,531		12,828			11,288			15,148
Aviation	S		2,596			15,313			8,586			6,191		9,395		18,154			10,760			4,509
Credit/ Surety	S		1,118			2,569			1,530			23,555		9,058		369			2,440			8,828
General Casualty	L		17,658			18,505			6,724			42,398		15,607		31,167			10,225			36,892
Marine & Energy	S		(1,549	)		8,826			5,220			21,128		4,033		8,565			(3,731	)		37,799
Medical Malpractice	L		19,554			(3,131	)		6,424			33,804		11,093		7,077			21,783			36,417
Other	S		520			1,183			294			5,664		168		(57	)		485			3,011
Professional Liability	L		28,538			37,965			51,615			55,812		37,407		60,373			53,705			50,629
Property	S		6,296			34,859			96,745			138,958		2,260		34,240			118,581			142,118
Whole Account	S/L		426			(232	)		3,095			47,135		6,578		4,569			18,503			5,369
Workers’ Compensation	L		14,284			561			7,197			11,966		8,164		33,693			19,161			29,225
Aggregate Pro Forma Reinsurance Segment		$	110,620		$	124,004		$	197,146		$	460,618	$	125,447	$	210,882		$	262,938		$	461,141

[a] This information is based on historical Alterra reinsurance segment gross premiums written adjusted to include Harbor Point historical gross premiums written as though the amalgamation with Harbor Point had occurred on January 1, 2009. The financial information also includes adjustments to eliminate any intercompany transactions.

The pro forma information is provided for informational purposes only. The pro forma information does not necessarily represent results that would have occurred if the amalgamation with Harbor Point had occurred on January 1, 2009, nor is it necessarily indicative of future results.

17

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–NINE MONTHS ENDED SEPTEMBER 30, 2011 (Unaudited)

(Expressed in thousands of United States Dollars)

	Property & Casualty															Life & Annuity			Corporate			Consolidated
	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total			Reinsurance
Gross premiums written	$	298,523		$	780,558		$	241,995		$	254,820		$	1,575,896		$	2,187		$	—		$	1,578,083
Reinsurance premiums ceded		(142,443	)		(81,438	)		(85,962	)		(54,820	)		(364,663	)		(211	)		—			(364,874	)
Net premiums written	$	156,080		$	699,120		$	156,033		$	200,000		$	1,211,233		$	1,976		$	—		$	1,213,209
Earned premiums	$	297,595		$	676,876		$	222,408		$	186,135		$	1,383,014		$	2,187		$	—		$	1,385,201
Earned premiums ceded		(140,646	)		(50,989	)		(71,515	)		(45,970	)		(309,120	)		(211	)		—			(309,331	)
Net premiums earned		156,949			625,887			150,893			140,165			1,073,894			1,976			—			1,075,870
Net losses and loss expenses		(87,305	)		(426,234	)		(97,725	)		(102,796	)		(714,060	)		—						(714,060	)
Claims and policy benefits		—			—			—			—			—			(44,818	)					(44,818	)
Acquisition costs		786			(137,807	)		(27,240	)		(32,035	)		(196,296	)		(426	)					(196,722	)
General and administrative expenses		(27,545	)		(63,868	)		(26,752	)		(28,494	)		(146,659	)		(581	)					(147,240	)
Other income (loss)		1,009			1,325			—			353			2,687			(31	)					2,656
Underwriting income (loss)		43,894			(697	)		(824	)		(22,807	)		19,566			n/a			—			n/a
Net investment income																	37,019			140,747			177,766
Net realized and unrealized losses on investments																	(4,899	)		(27,665	)		(32,564	)
Net impairment losses recognized in earnings																				(2,243	)		(2,243	)
Corporate other income																				723			723
Interest expense																				(30,392	)		(30,392	)
Net foreign exchange losses																				(2,065	)		(2,065	)
Corporate general and administrative expenses																				(55,177	)		(55,177	)
(Loss) income before taxes																$	(11,760	)	$	23,928		$	31,734
Loss ratio [a]		55.6	%		68.1	%		64.8	%		73.3	%		66.5	%
Acquisition cost ratio [b]		(0.5	%)		22.0	%		18.1	%		22.9	%		18.3	%
General and administrative expense ratio [c]		17.6	%		10.2	%		17.7	%		20.3	%		13.7	%
Combined ratio [d]		72.7	%		100.3	%		100.5	%		116.5	%		98.4	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned for the property & casualty business.

[b] The acquisition cost ratio is calculated by dividing acquisition costs by net premiums earned for the property & casualty business.

[c] The general and administrative expense ratio is calculated by dividing general and administrative expenses by net premiums earned for the property & casualty business.

[d] The combined ratio is calculated by dividing the sum of net losses and loss expenses, acquisition costs and general and administrative expenses by net premiums earned for the property & casualty business.

Percentage totals may not add due to rounding.

18

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED UNDERWRITING RATIOS - NINE MONTHS ENDED SEPTEMBER 30, 2011 (Unaudited)

	Property & Casualty
	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total
UNDERWRITING RATIOS
Loss ratio		55.6	%		68.1	%		64.8	%		73.3	%		66.5	%
Acquisition cost ratio		(0.5	%)		22.0	%		18.1	%		22.9	%		18.3	%
General and administrative expense ratio		17.6	%		10.2	%		17.7	%		20.3	%		13.7	%
Combined ratio		72.7	%		100.3	%		100.5	%		116.5	%		98.4	%
EFFECT OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT FAVORABLE / (UNFAVORABLE)
Loss ratio [a]		26.5	%		9.3	%		(1.0	%)		8.5	%		10.3	%
NET OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT UNDERWRITING RATIOS
Loss ratio		82.1	%		77.4	%		63.8	%		81.8	%		76.8	%
Acquisition cost ratio		(0.5	%)		22.0	%		18.1	%		22.9	%		18.3	%
General and administrative expense ratio		17.6	%		10.2	%		17.7	%		20.3	%		13.7	%
Combined ratio		99.2	%		109.7	%		99.6	%		125.0	%		108.8	%

[a] Prior accident year reserve development excludes changes in reserves resulting from changes in premium estimates on prior years’ contracts.

CONSOLIDATED UNDERWRITING RATIOS - NINE MONTHS ENDED SEPTEMBER 30, 2010 (Unaudited)

	Property & Casualty
	Insurance [b]			Reinsurance [c]			U.S. Specialty [b]			Alterra  at Lloyd’s			Total
UNDERWRITING RATIOS
Loss ratio		60.6	%		57.7	%		61.6	%		46.4	%		57.5	%
Acquisition cost ratio		1.1	%		21.4	%		16.0	%		19.5	%		16.1	%
General and administrative expense ratio		13.2	%		9.5	%		18.5	%		16.5	%		12.4	%
Combined ratio		74.8	%		88.7	%		96.1	%		82.3	%		86.1	%
EFFECT OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT FAVORABLE / (UNFAVORABLE)
Loss ratio [a]		19.1	%		8.1	%		0.6	%		9.1	%		9.4	%
NET OF PRIOR ACCIDENT YEAR RESERVE DEVELOPMENT
UNDERWRITING RATIOS
Loss ratio		79.6	%		65.7	%		62.2	%		52.8	%		67.1	%
Acquisition cost ratio		1.1	%		21.4	%		16.0	%		19.5	%		16.1	%
General and administrative expense ratio		13.2	%		9.5	%		18.5	%		16.5	%		12.4	%
Combined ratio		93.9	%		96.8	%		96.7	%		91.4	%		95.5	%

[a] Prior accident year reserve development excludes changes in reserves resulting from changes in premium estimates on prior years’ contracts.

[b] Insurance and U.S. Specialty segment amounts for the comparative 2010 period have been reclassified to conform with the current period’s presentation.

[c] Includes the results for Harbor Point from May 12, 2010.

Percentage totals may not add due to rounding.

19

ALTERRA CAPITAL HOLDINGS LIMITED

INSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE NINE MONTHS ENDED									FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010  [a]			Sept. 30, 2009  [a]			Dec. 31, 2010  [a]			Dec. 31, 2009  [a]
Gross premiums written	$	298,523		$	286,376		$	320,662		$	399,612		$	447,340
Reinsurance premiums ceded		(142,443	)		(123,963	)	$	(147,580	)		(180,691	)		(218,633	)
Net premiums written	$	156,080		$	162,413		$	173,082		$	218,921		$	228,707
Earned premiums	$	297,595		$	309,227		$	319,992		$	415,396		$	434,147
Earned premiums ceded		(140,646	)		(136,837	)		(160,644	)		(180,684	)		(216,687	)
Net premiums earned		156,949			172,390			159,348			234,712			217,460
Net losses and loss expenses		(87,305	)		(104,421	)		(112,574	)		(140,108	)		(140,403	)
Acquisition costs		786			(1,886	)		1,266			(3,651	)		1,206
General and administrative expenses		(27,545	)		(22,696	)		(20,881	)		(34,508	)		(27,927	)
Other income		1,009			1,199			1,578			1,267			1,620
Underwriting income	$	43,894		$	44,586		$	28,737		$	57,712		$	51,956
Loss ratio		55.6	%		60.6	%		70.6	%		59.7	%		64.6	%
Acquisition cost ratio		(0.5	%)		1.1	%		(0.8	%)		1.6	%		(0.6	%)
General and administrative expense ratio		17.6	%		13.2	%		13.1	%		14.6	%		12.7	%
Combined ratio		72.7	%		74.8	%		83.0	%		76.0	%		76.9	%

[a] Insurance and U.S. Specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation. See page 34 for additional information.

20

ALTERRA CAPITAL HOLDINGS LIMITED

REINSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE NINE MONTHS ENDED									FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010  [a]			Sept. 30, 2009			Dec. 31, 2010  [a]			Dec. 31, 2009
Gross premiums written	$	780,558		$	398,433		$	422,296		$	509,053		$	489,028
Reinsurance premiums ceded		(81,438	)		(61,223	)		(80,574	)		(64,131	)		(80,005	)
Net premiums written	$	699,120		$	337,210		$	341,722		$	444,922		$	409,023
Earned premiums	$	676,876		$	483,982		$	364,994		$	699,243		$	476,434
Earned premiums ceded		(50,989	)		(50,545	)		(74,711	)		(71,627	)		(88,578	)
Net premiums earned		625,887			433,437			290,283			627,616			387,856
Net losses and loss expenses		(426,234	)		(250,177	)		(192,756	)		(347,816	)		(254,474	)
Acquisition costs		(137,807	)		(92,708	)		(53,496	)		(131,114	)		(71,074	)
General and administrative expenses		(63,868	)		(41,359	)		(23,604	)		(66,073	)		(31,778	)
Other income		1,325			216			12			—			12
Underwriting (loss) income	$	(697	)	$	49,409		$	20,439		$	82,613		$	30,542
Loss ratio		68.1	%		57.7	%		66.4	%		55.4	%		65.6	%
Acquisition cost ratio		22.0	%		21.4	%		18.5	%		20.9	%		18.3	%
General and administrative expense ratio		10.2	%		9.5	%		8.1	%		10.5	%		8.2	%
Combined ratio		100.3	%		88.7	%		93.0	%		86.8	%		92.1	%

[a] Includes the results for Harbor Point from May 12, 2010.

21

ALTERRA CAPITAL HOLDINGS LIMITED

U.S. SPECIALTY SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE NINE MONTHS ENDED									FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010  [a]			Sept. 30, 2009  [a]			Dec. 31, 2010  [a]			Dec. 31, 2009  [a]
Gross premiums written	$	241,995		$	228,873		$	201,333		$	294,498		$	265,905
Reinsurance premiums ceded		(85,962	)		(72,537	)		(117,075	)		(88,493	)		(148,546	)
Net premiums written	$	156,033		$	156,336		$	84,258		$	206,005		$	117,359
Earned premiums	$	222,408		$	213,587		$	173,326		$	288,270		$	239,613
Earned premiums ceded		(71,515	)		(91,517	)		(108,748	)		(117,657	)		(149,008	)
Net premiums earned		150,893			122,070			64,578			170,613			90,605
Net losses and loss expenses		(97,725	)		(75,174	)		(39,955	)		(107,052	)		(54,764	)
Acquisition costs		(27,240	)		(19,556	)		(5,636	)		(28,174	)		(7,474	)
General and administrative expenses		(26,752	)		(22,570	)		(18,139	)		(30,122	)		(27,925	)
Other income (loss)		—			—			(68	)		—			(68	)
Underwriting (loss) income	$	(824	)	$	4,770		$	780		$	5,265		$	374
Loss ratio		64.8	%		61.6	%		61.9	%		62.7	%		60.4	%
Acquisition cost ratio		18.1	%		16.0	%		8.7	%		16.5	%		8.2	%
General and administrative expense ratio		17.7	%		18.5	%		28.1	%		17.7	%		30.9	%
Combined ratio		100.5	%		96.1	%		98.7	%		96.9	%		99.5	%

[a] Insurance and U.S. Specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation. See page 34 for additional information.

22

ALTERRA CAPITAL HOLDINGS LIMITED

ALTERRA AT LLOYD’S SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE NINE MONTHS ENDED									FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010			Sept. 30, 2009			Dec. 31, 2010			Dec. 31, 2009
Gross premiums written	$	254,820		$	178,653		$	110,629		$	202,633		$	128,973
Reinsurance premiums ceded		(54,820	)		(35,589	)		(31,963	)		(37,448	)		(32,884	)
Net premiums written	$	200,000		$	143,064		$	78,666		$	165,185		$	96,089
Earned premiums	$	186,135		$	123,170		$	93,811		$	170,803		$	125,000
Earned premiums ceded		(45,970	)		(23,899	)		(22,539	)		(35,793	)		(29,907	)
Net premiums earned		140,165			99,271			71,272			135,010			95,093
Net losses and loss expenses		(102,796	)		(46,022	)		(33,444	)		(59,865	)		(43,958	)
Acquisition costs		(32,035	)		(19,311	)		(14,797	)		(24,164	)		(18,136	)
General and administrative expenses		(28,494	)		(16,345	)		(15,856	)		(28,531	)		(19,972	)
Other income		353			528			475			2,534			658
Underwriting (loss) income	$	(22,807	)	$	18,121		$	7,650		$	24,984		$	13,685
Loss ratio		73.3	%		46.4	%		46.9	%		44.3	%		46.2	%
Acquisition cost ratio		22.9	%		19.5	%		20.8	%		17.9	%		19.1	%
General and administrative expense ratio		20.3	%		16.5	%		22.2	%		21.1	%		21.0	%
Combined ratio		116.5	%		82.3	%		89.9	%		83.4	%		86.3	%

23

ALTERRA CAPITAL HOLDINGS LIMITED

LIFE AND ANNUITY REINSURANCE SEGMENT DATA (Unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE NINE MONTHS ENDED									FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010			Sept. 30, 2009			Dec. 31, 2010			Dec. 31, 2009
Gross premiums written	$	2,187		$	2,998		$	41,748		$	4,935		$	43,755
Reinsurance premiums ceded		(211	)		(234	)		(146	)		(400	)		(413	)
Net premiums written	$	1,976		$	2,764		$	41,602		$	4,535		$	43,342
Earned premiums	$	2,187		$	2,998		$	41,748		$	4,935		$	43,755
Earned premiums ceded		(211	)		(234	)		(146	)		(400	)		(413	)
Net premiums earned		1,976			2,764			41,602			4,535			43,342
Net investment income		37,019			37,701			37,626			49,785			50,993
Net realized and unrealized (losses) gains on investments		(4,899	)		7,377			29,146			11,358			37,338
Other income (loss)		(31	)		(71	)		—			286			(120	)
Claims and policy benefits		(44,818	)		(46,662	)		(84,117	)		(65,213	)		(101,093	)
Acquisition costs		(426	)		(440	)		(1,023	)		(361	)		(1,396	)
General and administrative expenses		(581	)		(1,876	)		(2,180	)		(2,964	)		(2,786	)
(Loss) income before taxes	$	(11,760	)	$	(1,207	)	$	21,054		$	(2,574	)	$	26,278

24

ALTERRA CAPITAL HOLDINGS LIMITED

SEGMENT GROSS PREMIUMS WRITTEN BY LINE OF BUSINESS (Unaudited)

(Expressed in thousands of United States Dollars)

		FOR THE NINE MONTHS ENDED						FOR THE YEARS ENDED
		Sept. 30, 2011		Sept. 30, 2010		Sept. 30, 2009		Dec. 31, 2010		Dec. 31, 2009
Property & Casualty:
Insurance [a]:
Aviation	S	$	11,966	$	17,211	$	30,314	$	39,888	$	69,834
Excess Liability	L		92,942		86,212		105,019		113,573		133,340
Professional Liability	L		132,302		131,852		134,845		183,051		179,904
Property	S		61,313		51,101		50,484		63,100		64,262
			298,523		286,376		320,662		399,612		447,340
Reinsurance [b]:
Agriculture	S		30,496		30,628		87,338		29,222		89,550
Auto	S		79,259		10,317		—		32,902		—
Aviation	S		15,654		28,696		25,335		31,292		34,715
Credit/ Surety	S		33,098		1,078		—		2,196		—
General Casualty	L		60,862		30,699		23,404		48,357		29,185
Marine & Energy	S		20,605		17,930		14,722		16,381		18,321
Medical Malpractice	L		35,672		31,837		56,397		51,391		67,483
Other	S		3,318		2,264		2,268		2,784		2,297
Professional Liability	L		139,221		81,889		45,922		110,427		71,531
Property	S		300,757		141,850		89,414		148,146		87,039
Whole Account	S/L		33,392		4,703		8,509		5,129		11,456
Workers’ Compensation	L		28,224		16,542		68,987		30,826		77,451
			780,558		398,433		422,296		509,053		489,028
U.S. Specialty [a]:
General Liability	L		57,395		61,223		51,091		81,137		68,209
Marine	S		64,687		49,696		45,917		67,454		61,360
Professional Liability	L		13,668		7,136		—		6,602		576
Property	S		106,245		110,818		104,325		139,305		135,760
			241,995		228,873		201,333		294,498		265,905
Alterra at Lloyd’s:
Accident & Health	S		31,447		25,351		21,357		30,921		22,602
Aviation	S		7,707		10,914		—		16,138		2,611
Financial Institutions	L		19,068		19,064		18,376		19,448		23,822
International Casualty	L		50,351		23,961		—		26,174		—
Professional Liability	L		18,828		15,387		14,599		19,591		19,889
Property	S		126,070		79,607		56,297		85,553		60,049
Surety	S		1,349		4,369		—		4,808		—
			254,820		178,653		110,629		202,633		128,973
Aggregate Property & Casualty		$	1,575,896	$	1,092,335	$	1,054,920	$	1,405,796	$	1,331,246
Life & Annuity:
Annuity		$	1,056	$	6	$	—	$	1,135	$	—
Life			1,131		2,992		41,748		3,800		43,755
Aggregate Life & Annuity		$	2,187	$	2,998	$	41,748	$	4,935	$	43,755
Aggregate Property & Casualty and Life & Annuity		$	1,578,083	$	1,095,333	$	1,096,668	$	1,410,731	$	1,375,001

[a] Insurance and U.S. Specialty segment amounts for comparative periods have been reclassified to conform with the current period’s presentation.

[b] Includes the results for Harbor Point from May 12, 2010.

S = Short tail lines	$	910,667	$	584,182	$	532,025	$	712,655	$	654,128
L = Long tail lines		665,229		508,153		522,895		693,141		677,118
Aggregate Property & Casualty	$	1,575,896	$	1,092,335	$	1,054,920	$	1,405,796	$	1,331,246

25

ALTERRA CAPITAL HOLDINGS LIMITED

INVESTMENT PORTFOLIO (Unaudited)

(Expressed in thousands of United States Dollars

Type of Investment	Carrying Value										Fair Value
	As of Sept. 30, 2011		Investment Distribution			As of Dec. 31, 2010		Investment Distribution			As of Sept. 30, 2011		Investment Distribution			As of Dec. 31, 2010		Investment Distribution
Cash and cash equivalents	$	869,975		10.9	%	$	905,606		11.5	%	$	869,975		10.7	%	$	905,606		11.4	%
U.S. government and agencies		856,923		10.7	%		995,546		12.7	%		856,923		10.5	%		995,546		12.5	%
Non-U.S. governments		185,283		2.3	%		79,111		1.0	%		185,283		2.3	%		79,111		1.0	%
Corporate securities		2,781,212		34.8	%		2,735,366		34.8	%		2,781,212		34.1	%		2,735,366		34.5	%
Municipal securities		245,427		3.1	%		238,014		3.0	%		245,427		3.0	%		238,014		3.0	%
Asset-backed securities		240,584		3.0	%		86,937		1.1	%		240,584		3.0	%		86,937		1.1	%
Residential mortgage-backed securities		1,222,528		15.3	%		1,168,390		14.9	%		1,222,528		15.0	%		1,168,390		14.7	%
Commercial mortgage-backed securities		358,665		4.5	%		334,151		4.3	%		358,665		4.4	%		334,151		4.2	%
Fixed maturities carried at fair value	$	5,890,622		73.6	%	$	5,637,515		71.7	%	$	5,890,622		72.3	%	$	5,637,515		71.0	%
Other investments carried at fair value	$	311,633		3.9	%	$	378,128		4.8	%	$	311,633		3.8	%	$	378,128		4.8	%
Total investments carried at fair value	$	7,072,230		88.4	%	$	6,921,249		88.0	%	$	7,072,230		86.8	%	$	6,921,249		87.2	%
U.S. government and agencies	$	29,697		0.4	%	$	29,687		0.4	%	$	33,276		0.4	%	$	30,200		0.4	%
Non-U.S. governments		539,409		6.7	%		538,274		6.8	%		644,840		7.9	%		587,053		7.4	%
Corporate securities		356,810		4.5	%		371,143		4.7	%		394,053		4.8	%		397,261		5.0	%
Asset-backed securities		1,000		0.0	%		1,000		0.0	%		1,005		0.0	%		998		0.0	%
Fixed maturities carried at amortized cost	$	926,916		11.6	%	$	940,104		12.0	%	$	1,073,174		13.2	%	$	1,015,512		12.8	%
Total invested assets	$	7,999,146		100.0	%	$	7,861,353		100.0	%	$	8,145,404		100.0	%	$	7,936,761		100.0	%

As of September 30, 2011, the weighted average book yield of the cash and fixed maturities portfolio was 3.35%, and the weighted average duration was 4.2 years.

Credit Ratings	As of Sept. 30, 2011		Ratings Distribution			As of Dec. 31, 2010		Ratings Distribution			As of Sept. 30, 2011		Ratings Distribution			As of Dec. 31, 2010		Ratings Distribution
U.S. government and agencies [a]	$	1,971,023		28.9	%	$	2,060,116		31.3	%	$	1,971,023		28.3	%	$	2,060,116		31.0	%
AAA		1,045,128		15.3	%		1,076,680		16.4	%		1,045,128		15.0	%		1,076,680		16.2	%
AA		891,470		13.1	%		657,867		10.0	%		891,470		12.8	%		657,867		9.9	%
A		1,393,419		20.4	%		1,353,945		20.6	%		1,393,419		20.0	%		1,353,945		20.4	%
BBB		253,442		3.7	%		226,849		3.4	%		253,442		3.6	%		226,849		3.4	%
BB		78,711		1.2	%		32,021		0.5	%		78,711		1.1	%		32,021		0.5	%
B		129,293		1.9	%		138,703		2.1	%		129,293		1.9	%		138,703		2.1	%
CCC or lower		51,226		0.8	%		45,469		0.7	%		51,226		0.7	%		45,469		0.7	%
Not rated		76,910		1.1	%		45,865		0.7	%		76,910		1.1	%		45,865		0.7	%
Fixed maturities carried at fair value	$	5,890,622		86.4	%	$	5,637,515		85.7	%	$	5,890,622		84.6	%	$	5,637,515		84.7	%
U.S. government and agencies	$	29,697		0.4	%	$	29,687		0.5	%	$	33,277		0.5	%	$	30,200		0.5	%
AAA		641,925		9.4	%		641,437		9.8	%		764,822		11.0	%		699,598		10.5	%
AA		110,497		1.6	%		113,140		1.7	%		116,735		1.7	%		118,276		1.8	%
A		124,734		1.8	%		141,683		2.2	%		136,366		2.0	%		151,127		2.3	%
BBB		20,063		0.3	%		12,744		0.2	%		21,974		0.3	%		14,764		0.2	%
Not rated		—		—			1,413		0.0	%		—		—			1,547		0.0	%
Fixed maturities carried at amortized cost	$	926,916		13.6	%	$	940,104		14.3	%	$	1,073,174		15.4	%	$	1,015,512		15.3	%
Total fixed maturities	$	6,817,538		100.0	%	$	6,577,619		100.0	%	$	6,963,796		100.0	%	$	6,653,027		100.0	%

[a] Included within U.S. government and agencies are agency-issued residential mortgage-backed securities with a fair value of $1,114,100 (December 31, 2010: $1,064,570).

Percentage totals may not add due to rounding.

	Quarter Ended Sept. 30, 2011			Quarter Ended June 30, 2011			Quarter Ended Mar. 31, 2011			Quarter Ended Dec. 31, 2010			Quarter Ended Sept. 30, 2010			Quarter Ended Sept. 30, 2009
Net investment income	$	60,335		$	59,665		$	57,766		$	61,080		$	59,711		$	42,830
Realized and unrealized gains (losses) on trading fixed maturities	$	1,663		$	1,432		$	(1,827	)	$	(3,893	)	$	883		$	1,400
Net realized gains (losses) on available for sale fixed maturities		6,096			54			3,369			5,816			6,395			(655	)
(Decrease) increase in fair value of hedge funds		(7,669	)		(1,878	)		3,167			5,465			4,820			23,200
(Decrease) increase in fair value of non-hedge fund other investments		(8,062	)		(5,382	)		(23,527	)		2,437			3,313			583
Net realized and unrealized (losses) gains on investments	$	(7,972	)	$	(5,774	)	$	(18,818	)	$	9,825		$	15,411		$	24,528
Net impairment losses recognized in earnings	$	(861	)	$	(353	)	$	(1,029	)	$	(1,774	)	$	(151	)	$	(139	)

26

ALTERRA CAPITAL HOLDINGS LIMITED

INVESTMENT PORTFOLIO (Unaudited)

(Expressed in thousands of United States Dollars)

	As of Sept. 30, 2011			Periodic Rate of Return
				Last 3 Months	Year to Date			Last 12 months			Last 60 months*
Cash and fixed maturities	$	7,687,513		1.62%		4.77	%		3.33	%		5.33	%
Distressed securities	$	26,227		(3.27%)		(0.99	%)		1.62	%		4.97	%
Diversified arbitrage		20,097		(1.47%)		(3.51	%)		2.39	%		(1.28	%)
Emerging markets		4,948		(0.27%)		0.65	%		2.73	%		4.42	%
Event-driven arbitrage		25,527		(4.38%)		(7.84	%)		(6.36	%)		2.11	%
Fixed income arbitrage		—		0.00%		0.00	%		0.00	%		13.01	%
Fund of funds		31,576		(2.77%)		0.19	%		3.07	%		0.91	%
Global macro		50,385		3.36%		2.67	%		4.54	%		6.17	%
Long / short credit		9,420		(4.08%)		(6.15	%)		(4.04	%)		3.00	%
Long / short equity		105,702		(4.00%)		(1.28	%)		0.24	%		5.88	%
Opportunistic		1,694		(0.30%)		(36.79	%)		(36.81	%)		(21.00	%)
Hedge funds **		275,576		(2.33%)		(1.81	%)		(0.28	%)		2.63	%
Derivatives		(3,062	)
Structured deposits		24,852
Equity investments		14,267
Total other investments	$	311,633
Total invested assets	$	7,999,146

Hedge Fund Investment Return Data:

HFRI Fund of Funds Composite Index [a] (4.96 %)  (5.26 %)  (1.83 %)  0.40 % 

Hedge Fund Performance History – 60 months ended Sept. 30, 2011
	2011			2010			2009			2008			2007			2006
Monthly performance
January		0.13	%		0.79	%		2.13	%		(1.37	%)		1.28	%
February		0.57	%		0.17	%		0.65	%		1.83	%		1.50	%
March		0.29	%		1.02	%		(0.76	%)		(2.58	%)		1.90	%
April		0.73	%		0.88	%		(0.84	%)		(0.13	%)		2.30	%
May		(0.28	%)		(0.73	%)		2.45	%		2.51	%		2.59	%
June		(0.89	%)		(0.83	%)		1.53	%		0.93	%		0.85	%
July		0.15	%		0.36	%		1.40	%		(4.12	%)		0.99	%
August		(1.37	%)		(0.28	%)		0.78	%		(2.14	%)		(1.62	%)
September		(1.13	%)		1.28	%		1.71	%		(7.31	%)		1.85	%
October					0.84	%		1.53	%		(4.85	%)		4.15	%		1.37	%
November					0.40	%		0.35	%		(1.75	%)		0.10	%		1.81	%
December					0.31	%		0.77	%		(1.92	%)		(0.13	%)		1.96	%
Quarterly performance
Q1		0.98	%		1.99	%		2.00	%		(2.15	%)		4.75	%
Q2		(0.45	%)		(0.69	%)		3.14	%		3.33	%		5.83	%
Q3		(2.33	%)		1.35	%		3.94	%		(13.03	%)		1.18	%
Q4					1.56	%		2.66	%		(8.31	%)		4.11	%		5.22	%
Period return		(1.81	%)		4.25	%		12.27	%		(19.38	%)		16.78	%		5.22	%

Past performance should not be considered to be a reliable indicator of future performance.

[a] As reported by HFRI as of October 28, 2011

* Annualized

** Net of all fees

27

ALTERRA CAPITAL HOLDINGS LIMITED

LARGEST 25 CORPORATE HOLDINGS (Unaudited)

(Expressed in thousands of United States Dollars)

	As of Sept. 30, 2011
	Amortized Cost			Fair Value
Issuer
General Electric		57,171			58,561
Bank of America Corp		59,140			54,576
JP Morgan Chase & Co		52,869			54,374
Wells Fargo & Co		43,965			44,938
Morgan Stanley		44,351			43,099
Citigroup Inc		44,300			42,820
Lloyds Banking Group plc		39,026			39,392
Pepsico Inc		35,806			37,883
BP plc		35,478			36,613
Credit Suisse Group		36,661			36,364
AT&T Inc		33,731			35,605
Novartis AG		33,027			34,980
Verizon Communications Inc		32,468			34,435
Goldman Sachs Group Inc		31,769			31,136
UBS AG		29,421			30,765
Pfizer Inc		26,692			28,659
Conoco Philips		25,490			27,739
Berkshire Hathaway Inc		27,220			27,729
Metlife Inc		25,278			26,617
Wal-Mart Stores Inc		24,162			26,454
Hypo Real Estate Holding AG		26,092			26,211
Barclays plc		25,606			24,053
Medtronic Inc.		22,481			23,798
HSBC Holdings plc		23,610			23,738
Duke Energy Corp.		21,582	��		23,230
	$	857,395		$	873,769

28

ALTERRA CAPITAL HOLDINGS LIMITED

SHAREHOLDER RETURN ANALYSIS (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	FOR THE QUARTERS ENDED						FOR THE NINE MONTHS ENDED						FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010			Sept. 30, 2011			Sept. 30, 2010			Dec. 31, 2010			Dec. 31, 2009
Income and Return on Equity:
Net income	$	48,386		$	82,837		$	34,334		$	222,665		$	302,335		$	246,215
Net operating income	$	50,082		$	76,041		$	64,915		$	175,496		$	251,712		$	208,907
Average shareholders’ equity	$	2,818,910		$	2,981,752		$	2,799,260		$	2,297,438		$	2,467,429		$	1,398,872
Annualized return on average shareholders’ equity [a]		6.9	%		11.1	%		1.6	%		12.9	%		12.3	%		17.6	%
Annualized net operating return on average shareholders’ equity [a]		7.1	%		10.2	%		3.1	%		10.2	%		10.2	%		14.9	%
Book value and dividends per share:
Diluted book value per share	$	27.18		$	25.88		$	27.18		$	25.88		$	25.99		$	27.36
Dividends paid per share	$	0.14		$	0.12		$	0.38		$	2.82		$	2.94		$	0.38
Change in diluted book value per share		4.6	%		5.4	%		4.6	%		(5.4	%)		(5.0	%)		21.8	%
Dividend payout ratio [b]		0.5	%		0.5	%		1.4	%		21.5	%		22.4	%		1.7	%
Total return to shareholders [c]		5.1	%		5.9	%		5.9	%		16.1	%		17.4	%		23.5	%

[a] Annualized return on average shareholders’ equity is defined as annualized net income divided by the average of the quarterly average shareholders’ equity balances. Annualized net operating return on average shareholders’ equity is defined as annualized net operating income divided by the average of the quarterly average shareholders’ equity balances. The average shareholders’ equity for the nine months ended September 30, 2010 and the year ended December 31, 2010 has been weighted to include Harbor Point from May 12, 2010.

[b] Dividend payout ratio is calculated as dividends paid divided by beginning shareholders’ equity.

[c] Total return to shareholders is calculated as the change in diluted book value per share plus the dividend payout ratio.

29

ALTERRA CAPITAL HOLDINGS LIMITED

EARNINGS PER SHARE INFORMATION (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	FOR THE QUARTERS ENDED				FOR THE NINE MONTHS ENDED				FOR THE YEARS ENDED
	Sept. 30, 2011		Sept. 30, 2010		Sept. 30, 2011		Sept. 30, 2010		Dec. 31, 2010		Dec. 31, 2009
Net income available to common shareholders	$	48,386	$	82,837	$	34,334	$	222,665	$	302,335	$	246,215
Denominator:
Weighted average shares - basic
Outstanding [a]		104,589,483		117,036,803		105,644,318		87,965,467		94,426,055		56,615,080
Unvested restricted share units		240,817		163,702		222,453		288,142		256,224		391,828
		104,830,300		117,200,505		105,866,771		88,253,609		94,682,279		57,006,908
Share equivalents:
Warrants		521,292		492,718		948,670		515,265		537,399		608,161
Options		95,228		154,142		131,600		194,219		183,258		150,669
Employee stock purchase plan		1,909		2,301		1,472		2,330		2,301		1,399
Non participating restricted shares		216,553		108,276		144,369		36,092		54,138		—
Weighted average shares - diluted [b]		105,665,282		117,957,942		107,092,882		89,001,515		95,459,375		57,767,137
Net income per share	$	0.46	$	0.71	$	0.32	$	2.52	$	3.19	$	4.32
Net income per diluted share	$	0.46	$	0.70	$	0.32	$	2.50	$	3.17	$	4.26

[a] Includes weighted average unvested participating restricted shares.

[b] Computed using the treasury method. The treasury method assumes that the proceeds received from the exercise of options or warrants will be used to repurchase the Company’s common shares at the average market price during the period of calculation.

30

ALTERRA CAPITAL HOLDINGS LIMITED

OPERATING INCOME RECONCILIATION (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	FOR THE QUARTERS ENDED						FOR THE NINE MONTHS ENDED					FOR THE YEARS ENDED
	Sept. 30, 2011			Sept. 30, 2010			Sept. 30, 2011		Sept. 30, 2010			Dec. 31, 2010			Dec. 31, 2009
Before tax
Net income	$	52,813		$	83,695		$	31,734	$	227,848		$	306,491		$	256,236
Net realized and unrealized losses (gains) on non-hedge fund investments, before tax [a]		1,164			(10,440	)		28,427		2,692			65			(2,173	)
Foreign exchange (gains) losses, before tax		(147	)		3,353			2,065		267			(115	)		(5,772	)
Merger and acquisition expenses, before tax		—			550			—		(49,276	)		(48,776	)		(31,566	)
Net operating income		53,830			77,158			62,226		181,531			257,665			216,725
Net of tax
Net income	$	48,386		$	82,837		$	34,334	$	222,665		$	302,335		$	246,215
Net realized and unrealized losses (gains) on non-hedge fund investments, net of tax [a]		1,807			(10,104	)		29,120		2,672			(865	)		(1,411	)
Foreign exchange (gains) losses, net of tax		(111	)		2,758			1,461		780			363			(4,331	)
Merger and acquisition expenses, net of tax		—			550			—		(50,621	)		(50,121	)		(31,566	)
Net operating income		50,082			76,041			64,915		175,496			251,712			208,907
Weighted average shares outstanding:
Basic		104,830,300			117,200,505			105,866,771		88,253,609			94,682,279			57,006,908
Diluted		105,665,282			117,957,942			107,092,882		89,001,515			95,459,375			57,767,137
Basic per share data
Earnings per share	$	0.46		$	0.71		$	0.32	$	2.52		$	3.19		$	4.32
Net realized and unrealized losses (gains) on non-hedge fund investments, net of tax [a]		0.02			(0.09	)		0.28		0.03			(0.01	)		(0.02	)
Foreign exchange (gains) losses, net of tax		—			0.03			0.01		0.01			0.01			(0.08	)
Merger and acquisition expenses, net of tax		—			—			—		(0.57	)		(0.53	)		(0.56	)
Net operating income per share	$	0.48		$	0.65		$	0.61	$	1.99		$	2.66		$	3.66
Diluted per share data
Diluted earnings per share	$	0.46		$	0.70		$	0.32	$	2.50		$	3.17		$	4.26
Net realized and unrealized losses (gains) on non-hedge fund investments, net of tax [a]		0.02			(0.08	)		0.27		0.03			(0.01	)		(0.02	)
Foreign exchange (gains) losses, net of tax		—			0.02			0.01		0.01			0.01			(0.07	)
Merger and acquisition expenses, net of tax		—			—			—		(0.57	)		(0.53	)		(0.55	)
Net operating income per diluted share	$	0.47		$	0.64		$	0.61	$	1.97		$	2.64		$	3.62

[a] Net realized and unrealized (gains) losses on non-hedge fund investments includes realized and unrealized (gains) losses on trading securities, realized (gains) losses on available for sale securities, net impairment losses recognized in earnings, earnings from equity method investments and changes in fair value of investment derivatives, catastrophe bonds and structured deposits.

Per share totals may not add due to rounding.

31

ALTERRA CAPITAL HOLDINGS LIMITED

BOOK VALUE PER SHARE (Unaudited)

(Expressed in thousands of United States Dollars, except per share and share amounts)

	As of Sept. 30,  2011		As of June 30,  2011		As of Mar. 31, 2011		As of Dec. 31,  2010
Price per share at period end	$	18.97	$	22.30	$	22.26	$	21.64
Shareholders’ equity	$	2,844,738	$	2,793,081	$	2,723,194	$	2,918,270
Goodwill and intangible assets	$	56,652	$	58,094	$	58,585	$	59,076
Tangible book value	$	2,788,086	$	2,734,987	$	2,664,609	$	2,859,194
Basic common shares outstanding [a]		104,323,873		105,794,521		105,733,610		110,963,160
Add: unvested restricted stock units		258,393		247,179		247,179		167,971
Add: dilutive impact of warrants outstanding		—		1,334,909		1,346,672		1,036,442
Add: dilutive impact of options outstanding		79,386		123,881		134,901		123,395
Add: dilutive impact of employee stock purchase plan		3,557		—		4,016		—
Diluted shares outstanding [b]		104,665,209		107,500,490		107,466,378		112,290,968
Basic book value per share	$	27.27	$	26.40	$	25.76	$	26.30
Diluted book value per share	$	27.18	$	25.98	$	25.34	$	25.99
Basic tangible book value per share	$	26.73	$	25.85	$	25.20	$	25.77
Diluted tangible book value per share	$	26.64	$	25.44	$	24.79	$	25.46

[a] Includes unvested restricted shares

[b] Computed using the treasury method. The treasury method assumes that the proceeds received from the exercise of options or warrants will be used to repurchase the Company’s common shares at the period-end market price.

32

ALTERRA CAPITAL HOLDINGS LIMITED

REGULATION G

In presenting the Company’s results, management has included and discussed net operating income, net operating income per share, net operating income per diluted share, annualized net operating return on average shareholders’ equity, tangible book value per share and diluted tangible book value per share. These measures are “non-GAAP financial measures” as defined in Regulation G. Management believes that these non-GAAP financial measures, which may be defined differently by other companies, allow for a more complete understanding of the Company’s business. These measures, however, should not be viewed as a substitute for those determined in accordance with U.S. GAAP. The reconciliation of such measures to their respective most directly comparable U.S. GAAP financial measures is presented in the attached financial information in accordance with Regulation G.

Net operating income is defined as net income excluding after-tax net realized and unrealized gains or losses on non- hedge fund investments (this includes net realized and unrealized gains or losses on trading securities, net realized gains or losses on available for sale securities, net impairment losses recognized in earnings, changes in fair value of investment derivatives, catastrophe bonds, structured deposits and earnings from equity method investments), after-tax net foreign exchange gains or losses and after-tax merger and acquisition expenses. Net operating income per share and per diluted share is defined as the net operating income divided by the weighted average common shares or weighted average diluted common shares, respectively. We believe that this non-GAAP measure provides a better indication of management performance as realized and unrealized gains and losses on fixed maturities may fluctuate from period to period and foreign exchange gains and losses are typically outside the control of management. Merger and acquisition expenses are not indicative of expenses fundamental to the business and may fluctuate from period to period.

Annualized net operating return on average shareholders’ equity is defined as annualized net operating income divided by the average of the beginning and ending shareholders’ equity. Tangible book value is defined as shareholders’ equity excluding goodwill and intangible assets. Tangible book value per share and diluted tangible book value per share is defined as the tangible book value divided by the common shares outstanding or diluted common shares outstanding, respectively. These non-GAAP measures allow management to assess how the Company has performed in terms of wealth generated for its shareholders.

33

ALTERRA CAPITAL HOLDINGS LIMITED

Reclassified Segment Information

Selected Financial Information

34

ALTERRA CAPITAL HOLDINGS LIMITED

RECLASSIFICATION OF INSURANCE AND U.S. SPECIALTY SEGMENTS

(Expressed in thousands of United States Dollars)

INSURANCE SEGMENT

	Year ended						Year ended			Year ended						Year ended
	Dec. 31, 2010			Reclassified			Dec. 31, 2010			Dec. 31, 2009			Reclassified			Dec. 31, 2009
	(Reclassified)			amounts			(As previously reported)			(Reclassified)			amounts			(As previously reported)
Gross premiums written	$	399,612		$	29,492		$	370,120		$	447,340			$19,573		$	427,767
Reinsurance premiums ceded		(180,691	)		(10,083	)		(170,608	)		(218,633	)		(6,550	)		(212,083	)
Net premiums written	$	218,921		$	19,409		$	199,512		$	228,707			$13,023		$	215,684
Earned premiums	$	415,396		$	23,680		$	391,716		$	434,147			$17,057		$	417,090
Earned premiums ceded		(180,684	)		(7,561	)		(173,123	)		(216,687	)		(5,560)			(211,127	)
Net premiums earned		234,712			16,119			218,593			217,460			11,497			205,963
Net losses and loss expenses		(140,108	)		(11,285	)		(128,823	)		(140,403	)		(8,048)			(132,355	)
Acquisition costs		(3,651	)		(270	)		(3,381	)		1,206			(27)			1,233
General and administrative expenses		(34,508	)		(5,893	)		(28,615	)		(27,927	)		(3,304)			(24,623	)
Other income		1,267			507			760			1,620			382			1,238
Underwriting income (loss)	$	57,712		$	(822	)	$	58,534		$	51,956			$500		$	51,456
Loss ratio		59.7	%					58.9	%		64.6	%					64.3	%
Acquisition cost ratio		1.6	%					1.6	%		(0.6	%)					(0.6	%)
General and administrative expense ratio		14.7	%					13.1	%		12.9	%					11.9	%
Combined ratio		76.0	%					73.6	%		76.9	%					75.6	%

U.S. SPECIALTY SEGMENT

	Year ended						Year ended			Year ended					Year ended
	Dec. 31, 2010			Reclassified			Dec. 31, 2010			Dec. 31, 2009			Reclassified		Dec. 31, 2009
	(Reclassified)			amounts			(As previously reported)			(Reclassified)			amounts		(As previously reported)
Gross premiums written	$	294,498		$	(29,492	)	$	323,990		$	265,905			$(19,573)	$	285,478
Reinsurance premiums ceded		(88,493	)		10,083			(98,576	)		(148,546	)		6,550		(155,096	)
Net premiums written	$	206,005		$	(19,409	)	$	225,414		$	117,359			$(13,023)	$	130,382
Earned premiums	$	288,270		$	(23,680	)	$	311,950		$	239,613			$(17,057)	$	256,670
Earned premiums ceded		(117,657	)		7,561			(125,218	)		(149,008	)		5,560		(154,568	)
Net premiums earned		170,613			(16,119	)		186,732			90,605			(11,497)		102,102
Net losses and loss expenses		(107,052	)		11,285			(118,337	)		(54,764	)		8,048		(62,812	)
Acquisition costs		(28,174	)		270			(28,444	)		(7,474	)		27		(7,501	)
General and administrative expenses		(30,122	)		5,893			(36,015	)		(27,925	)		3,304		(31,229	)
Other income		—			(507	)		507			(68	)		(382)		314
Underwriting income (loss)	$	5,265		$	822		$	4,443		$	374			$(500)	$	874
Loss ratio		62.7	%					63.4	%		60.4	%				61.5	%
Acquisition cost ratio		16.5	%					15.2	%		8.2	%				7.3	%
General and administrative expense ratio		17.7	%					19.3	%		30.9	%				30.7	%
Combined ratio		96.9	%					97.9	%		99.5	%				99.5	%

Effective January 1, 2011, Alterra redefined its Insurance and U.S. Specialty segments based on changes to its internal reporting structure.

Insurance business underwritten by Alterra Insurance USA Inc., which was previously reported within the U.S. Specialty segment, has been reclassified to the Insurance segment. Alterra Insurance USA Inc. is a managing general underwriter for Alterra Excess & Surplus Insurance Company and Alterra America Insurance Company, as well as various third party insurance companies, and is Alterra’s principal insurance underwriting platform for retail distribution in the United States. Segment disclosures for comparative periods have been restated to reflect this reclassification.

35

ALTERRA CAPITAL HOLDINGS LIMITED

INSURANCE SEGMENT Results - as Reclassified (Unaudited)

(Expressed in thousands of United States Dollars)

	Dec. 31, 2010			Sept. 30, 2010			June 30, 2010			Mar. 31, 2010			Dec. 31, 2009			Sept. 30, 2009			June 30, 2009			Mar. 31, 2009
Gross premiums written	$	113,236		$	77,944		$	139,026		$	69,406		$	126,678		$	90,430		$	139,226		$	91,006
Reinsurance premiums ceded		(56,728	)		(36,875	)		(47,437	)		(39,651	)		(71,053	)		(43,388	)		(47,972	)		(56,220	)
Net premiums written	$	56,508		$	41,069		$	91,589		$	29,755		$	55,625		$	47,042		$	91,254		$	34,786
Earned premiums	$	106,169		$	102,640		$	104,841		$	101,746		$	114,155		$	108,776		$	105,576		$	105,640
Earned premiums ceded		(43,847	)		(42,796	)		(45,211	)		(48,830	)		(56,043	)		(56,337	)		(51,129	)		(53,178	)
Net premiums earned		62,322			59,844			59,630			52,916			58,112			52,439			54,447			52,462
Net losses and loss expenses		(35,687	)		(26,679	)		(38,296	)		(39,446	)		(27,829	)		(34,515	)		(39,901	)		(38,158	)
Acquisition costs		(1,765	)		(1,382	)		(821	)		317			(60	)		(331	)		230			1,367
General and administrative expenses		(11,812	)		(7,717	)		(8,132	)		(6,847	)		(7,046	)		(8,114	)		(6,693	)		(6,074	)
Other income		68			1,108			97			(6	)		42			143			219			1,216
Underwriting income	$	13,126		$	25,174		$	12,478		$	6,934		$	23,219		$	9,622		$	8,302		$	10,813
Loss ratio		57.3	%		44.6	%		64.2	%		74.5	%		47.9	%		65.8	%		73.3	%		72.7	%
Acquisition cost ratio		2.8	%		2.3	%		1.4	%		(0.6	%)		0.1	%		0.6	%		(0.4	%)		(2.6	%)
General and administrative expense ratio		18.9	%		12.9	%		13.6	%		13.0	%		12.1	%		15.5	%		12.3	%		11.6	%
Combined ratio		79.0	%		59.8	%		79.2	%		86.9	%		60.1	%		81.9	%		85.2	%		81.7	%

36

ALTERRA CAPITAL HOLDINGS LIMITED

U.S. SPECIALTY SEGMENT Results - as Reclassified (Unaudited)

(Expressed in thousands of United States Dollars)

	Dec. 31, 2010			Sept. 30, 2010			June 30, 2010			Mar. 31, 2010			Dec. 31, 2009			Sept. 30, 2009			June 30, 2009			Mar. 31, 2009
Gross premiums written	$	65,625		$	64,198		$	90,773		$	73,902		$	64,572		$	60,123		$	75,701		$	65,509
Reinsurance premiums ceded		(15,956	)		(18,713	)		(5,672	)		(48,152	)		(31,471	)		(24,755	)		(52,938	)		(39,382	)
Net premiums written	$	49,669		$	45,485		$	85,101		$	25,750		$	33,101		$	35,368		$	22,763		$	26,127
Earned premiums	$	74,683		$	73,337		$	71,065		$	69,185		$	66,287		$	63,360		$	59,053		$	50,913
Earned premiums ceded		(26,140	)		(26,071	)		(27,053	)		(38,393	)		(40,260	)		(35,551	)		(41,271	)		(31,926	)
Net premiums earned		48,543			47,266			44,012			30,792			26,027			27,809			17,782			18,987
Net losses and loss expenses		(31,878	)		(29,295	)		(26,683	)		(19,196	)		(14,809	)		(18,507	)		(11,057	)		(10,391	)
Acquisition costs		(8,618	)		(6,763	)		(9,111	)		(3,682	)		(1,838	)		(1,964	)		(2,483	)		(1,189	)
General and administrative expenses		(7,552	)		(8,693	)		(6,355	)		(7,522	)		(9,786	)		(6,971	)		(4,357	)		(6,811	)
Other income		—			—			—			—			—			—			153			(221	)
Underwriting income (loss)	$	495		$	2,515		$	1,863		$	392		$	(406	)	$	367		$	38		$	375
Loss ratio		65.7	%		62.0	%		60.6	%		62.3	%		56.9	%		66.6	%		62.2	%		54.7	%
Acquisition cost ratio		17.8	%		14.3	%		20.7	%		12.0	%		7.1	%		7.1	%		14.0	%		6.3	%
General and administrative expense ratio		15.5	%		18.4	%		14.5	%		24.4	%		37.6	%		25.0	%		24.4	%		35.9	%
Combined ratio		99.0	%		94.7	%		95.8	%		98.7	%		101.6	%		98.7	%		100.6	%		96.9	%

37

ALTERRA CAPITAL HOLDINGS LIMITED

Pro Forma Combined - Alterra Capital Holdings Limited and Harbor Point Limited Selected Financial Information

The following presentation is for informational purposes only

38

ALTERRA CAPITAL HOLDINGS LIMITED

PRO FORMA COMBINED STATEMENTS OF INCOME [a] (unaudited)

(Expressed in thousands of United States Dollars)

	FOR THE QUARTERS ENDED
	June 30, 2010			Mar. 31, 2010			Dec. 31, 2009			Sept. 30, 2009			June 30, 2009			Mar. 31, 2009
REVENUES
Gross premiums written	$	476,550		$	676,905		$	337,048		$	382,650		$	564,251		$	662,432
Reinsurance premiums ceded		(81,333	)		(159,515	)		(81,627	)		(73,703	)		(126,503	)		(168,155	)
Net premiums written	$	395,217		$	517,390		$	255,421		$	308,947		$	437,748		$	494,277
Net premiums earned	$	368,061		$	338,332		$	347,833		$	351,245		$	366,130		$	317,598
Net investment income		61,562			64,583			60,668			60,068			59,636			58,943
Net realized and unrealized (losses) gains on investments		(13,734	)		13,280			18,004			29,622			22,462			20,722
Net impairment losses recognized in earnings		(300	)		(420	)		(925	)		(139	)		(2,014	)		—
Net realized gain on retirement of senior notes		—			—			111			—			—			—
Other income		339			480			189			964			1,193			1,799
Total revenues		415,928			416,255			425,880			441,760			447,407			399,062
LOSSES AND EXPENSES
Net losses and loss expenses		213,517			210,543			166,573			181,064			186,301			178,130
Claims and policy benefits		13,943			17,659			16,976			14,378			55,407			14,332
Acquisition costs		64,315			53,998			54,042			59,613			53,317			47,611
Interest expense		8,061			5,226			6,978			6,292			5,146			4,351
Net foreign exchange (gains) losses		(1,622	)		(869	)		789			(116	)		(5,571	)		(1,911	)
Merger and acquisition expenses		—			—			—			(41,350	)		4,785			5,223
General and administrative expenses		60,137			51,611			66,157			57,048			53,979			57,508
Total losses and expenses		358,351			338,168			311,515			276,929			353,364			305,244
INCOME BEFORE TAXES		57,577			78,087			114,365			164,831			94,043			93,818
Income tax expense		4,294			1,311			5,686			2,910			3,206			1,990
NET INCOME		53,283			76,776			108,679			161,921			90,837			91,828

[a] This information is presented on a combined pro forma basis (after the elimination of intercompany transactions and the amortization of certain acquisition accounting fair value adjustments). The information is provided for informational purposes only to present a summary of the combined results of operations assuming the amalgamation with Harbor Point had occurred at the beginning of each calendar year presented. The information does not necessarily represent results that would have occurred if the amalgamation had taken place at the beginning of each calendar year presented, nor is it necessarily indicative of the future results.

39