Exhibit 99.1

ALTERRA CAPITAL REPORTS THIRD QUARTER 2010 RESULTS

Net Operating Income of $0.64 per Diluted Share

Book Value per Diluted Share Grows 5.4%

HAMILTON, BERMUDA, November 2, 2010—Alterra Capital Holdings Limited (NASDAQ: ALTE; BSX: ALTE.BH) (“Alterra”) today reported net income of $82.8 million, or $0.70 per diluted share, for the third quarter of 2010, compared to net income of $95.3 million, or $1.64 per diluted share, for the same quarter of 2009. Alterra, formerly known as Max Capital Group Ltd. (“Max”), was formed on May 12, 2010 by the merger of Max and Harbor Point Limited, a privately held company (“Harbor Point”).

Net operating income for the third quarter of 2010 was $76.0 million, or $0.64 per diluted share, compared to net operating income of $53.7 million, or $0.92 per diluted share, for the same quarter of 2009. Annualized net operating return on average shareholders’ equity for the third quarter of 2010 was 10.2%.

For the nine months ended September 30, 2010, Alterra reported net income of $222.7 million, or $2.50 per diluted share, compared to net income of $183.6 million, or $3.18 per diluted share, for the same period of 2009. Net operating income for the nine months ended September 30, 2010 was $175.5 million, or $1.97 per diluted share, compared to net operating income of $148.4 million, or $2.57 per diluted share, for the same period of 2009. Annualized net operating return on average shareholders’ equity for the nine months ended September 30, 2010 was 10.2%.

The results for Alterra include the results for Harbor Point and its subsidiaries from the date of the consummation of the merger on May 12, 2010. Comparative figures for 2009 represent the former Max results only. As a result, a comparison of Alterra’s gross premiums written from property and casualty underwriting and results of operations for the reinsurance segment for current and prior periods are not meaningful. Selected pro forma combined results of operations for periods prior to the merger for the reinsurance segment are provided in the third quarter financial supplement available on Alterra’s website at www.alterracap.com.

W. Marston (Marty) Becker, President and Chief Executive Officer of Alterra, said: “Alterra had a very solid quarter financially, and also operationally, with the Harbor Point merger integration proceeding as planned and now largely completed. Our balance sheet is very strong, and we are well positioned to respond to market opportunities as they arise.”

Mr. Becker added: “Our gross premiums written during the quarter were down on a pro forma basis, due in part to Alterra’s continued underwriting discipline in the face of a softening market, and to a related trend among primary companies to retain a greater share of business. Coupled with declining yields on invested assets, these factors added pressure to current operating income. We are pleased with the early results of our expansion into Latin America and the continued strong performance of our late 2008 Lloyd’s acquisition. Taken together with the quality underwriting teams that joined us as a result of our recent merger, we are strongly positioned both for today and for the future, with proven insurance and reinsurance capabilities in Bermuda, Dublin, London, and the U.S. – and now Latin America reinsurance as well.

“We remain focused and committed to prudent capital allocation as a means for delivering consistent shareholder value. During the quarter we continued our share repurchase program, buying back shares at an attractive discount to book value. For the year to date, we have returned over $435 million to shareholders in the form of dividends and share repurchases. We have also increased our capital flexibility this quarter by issuing long term debt at a favorable fixed rate of interest, reducing our allocation to short term variable rate borrowing. We believe this will prove beneficial in the future as interest rates inevitably rise from their current levels,” Mr. Becker concluded.

Third quarter 2010 results for Alterra include:

• Property and casualty gross premiums written of $323.9 million, representing an increase of $58.1 million, or 21.9%; net premiums written of $263.4 million, representing an increase of $80.9 million, or 44.3%; and net premiums earned of $341.2 million, representing an increase of $133.3 million, or 64.1%; each as compared to the same quarter of 2009. The percentage increases in these figures primarily reflect incremental growth from recent expansion initiatives, including the merger with Harbor Point - whose premiums are not included in the comparative 2009 results of operations - as well as from new operations in Latin America and new product offerings at Alterra at Lloyd’s. These increases were partially offset by decreases in previously existing operations where writings were reduced due to unattractive returns;

• Property and casualty combined ratio of 86.0% compared to 90.9% in the same quarter of 2009;

• Property catastrophe event and significant per-risk net losses of $14.1 million compared to no material property catastrophe losses in the same quarter of 2009;

• Net favorable development on prior years’ loss reserves of $36.4 million, or 10.6 combined ratio points, compared to $15.2 million, or 7.3 combined ratio points, in the same quarter of 2009;

• Net investment income of $59.7 million compared to $42.8 million in the same quarter of 2009, an increase of 39.5%; and

• Net operating income of $76.0 million, or $0.64 per diluted share, representing an annualized net operating return on average shareholders’ equity of 10.2%.

Gross premiums written from property and casualty underwriting for the third quarter of 2010 were $323.9 million, generated by the segments as follows: insurance - $70.3 million, a decrease of $10.8 million, or (13.3)%; reinsurance - $124.0 million, an increase of $29.9 million, or 31.8%; U.S. specialty - $71.9 million, an increase of $2.5 million, or 3.6%; and Alterra at Lloyd’s - $57.7 million, an increase of $36.6 million, or 173.5%. Gross premiums written included $30.2 million from our operations in Latin America, which started in the first quarter.

Segment combined ratios for the third quarter of 2010 were 56.5% for insurance, 91.1% for reinsurance, 95.4% for U.S. specialty and 90.4% for Alterra at Lloyd’s.

Results for the nine months ended September 30, 2010 include:

• Property and casualty gross premiums written of $1,092.3 million, representing an increase of $37.4 million, or 3.5%; net premiums written of $799.0 million, representing an increase of $121.3 million, or 17.9%; and net premiums earned of $827.2 million, representing an increase of $241.7 million, or 41.3%; each as compared to the same period of 2009. The percentage increases in these figures primarily reflect incremental growth from recent expansion initiatives, including the merger with Harbor Point - whose premiums are not included in the comparative 2009 results of operations - as well as from new operations in Latin America and new product offerings at Alterra at Lloyd’s. These increases were partially offset by decreases in previously existing operations where writings were reduced due to unattractive returns;

• Property and casualty combined ratio of 86.1% compared to 90.5% in the same period of 2009;

• Property catastrophe event and significant per-risk losses of $44.0 million compared to $3.4 million in the same period of 2009;

• Net favorable development on prior years’ loss reserves of $77.6 million, or 9.4 combined ratio points, compared to $47.5 million, or 8.1 combined ratio points, in the same period of 2009;

• Net investment income of $161.4 million compared to $125.1 million in the same period of 2009, an increase of 29.0%; and

• Net operating income of $175.5 million, or $1.97 per diluted share, representing an annualized net operating return on average shareholders’ equity of 10.2%.

Gross premiums written from property and casualty underwriting for the nine months ended September 30, 2010 were $1,092.3 million, generated by the segments as follows: insurance - $269.0 million, a decrease of $33.7 million, or (11.1)%; reinsurance - $398.4 million, a decrease of $23.9 million, or (5.7)%; U.S. specialty - $246.2 million, an increase of $26.9 million, or 12.3%; and Alterra at Lloyd’s - $178.7 million, an increase of $68.1 million, or 61.6%. There were no new contracts written within the life and annuity segment during the nine months ended September 30, 2010.

Segment combined ratios for the nine months ended September 30, 2010 were 72.7% for insurance, 88.7% for reinsurance, 96.9% for U.S. specialty and 82.3% for Alterra at Lloyd’s.

Balance Sheet

Total invested assets, including cash and cash equivalents, were $8.0 billion at September 30, 2010, an increase of $2.7 billion from December 31, 2009, primarily as a result of the merger. The credit quality of Alterra’s fixed maturities investment portfolio as of September 30, 2010 was high. As of September 30, 2010, 96.6% of the fixed maturities portfolio (by carrying value) was investment-grade, unchanged from December 31, 2009. As of September 30, 2010, the weighted average book yield of Alterra’s cash and fixed maturities portfolio was 3.23% and the weighted average duration was 4.1 years.

Net investment income for the third quarter of 2010 increased to $59.7 million from $42.8 million for the same quarter of 2009, and to $161.4 million from $125.1 million for the nine months ended September 30, 2010 and 2009, respectively. The increase in net investment income reflects the additional investment income from the Harbor Point investment portfolio since the consummation of the merger on May 12, 2010, and an increased allocation to higher-yielding fixed maturity securities.

Under the Board-approved share repurchase authorization, Alterra repurchased 2,845,356 of its common shares during the quarter ended September 30, 2010 at an average price of $19.00 per share for a total of $54.1 million. Share repurchases for the nine months ended September 30, 2010 were 5,052,349 common shares at an average price of $19.48 per share for a total of $98.4 million. As of September 30, 2010, $37.1 million remained under the Board-approved share repurchase authorization. On October 29, 2010, Alterra’s Rule 10b5-1 share repurchase plan expired by its terms. During October 2010, under the 10b5-1 plan, Alterra repurchased 699,900 common shares at an average price of $20.55 per share for a total of $14.4 million. Upon expiration of the 10b5-1 plan, $22.7 million remained available under the Board-approved share repurchase authorization.

Shareholders’ equity was $3,036.5 million as of September 30, 2010, an increase of 3.7% from June 30, 2010. Book value per diluted share as of September 30, 2010 was $25.88, an increase of 5.4% from June 30, 2010. Including the unrecognized change in fair value on Alterra’s held to maturity investment portfolio for the quarter ended September 30, 2010, the increase in book value per diluted share would have been 7.4%.

A copy of Alterra’s financial supplement for the third quarter will be available on Alterra’s website at www.alterracap.com shortly after the release of earnings.

Alterra will host a conference call on Wednesday, November 3, 2010 at 10:00am (EDT) to discuss its third quarter results with interested investors and shareholders. The conference call can be accessed via telephone by dialing 1-888-713-4218 (toll-free U.S.) or 1-617-213-4870 (international) and using access code 55954665. A live broadcast of the conference call will also be available through Alterra’s website at www.alterracap.com.

Alterra Capital Holdings Limited is a global enterprise dedicated to providing diversified specialty insurance and reinsurance products to corporations, public entities and property and casualty insurers.

Non-GAAP Financial Measures

In presenting Alterra’s results, management has included and discussed net operating income, net operating income per diluted share, annualized net operating return on average shareholders’ equity 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 Alterra’s business. These measures, however, should not be viewed as a substitute for those determined in accordance with U.S. GAAP. The reconciliation of these measures to their respective most directly comparable U.S. GAAP financial measures is presented in the attached financial information in accordance with Regulation G.

Cautionary Note Regarding Forward-Looking Statements

This release may include forward-looking statements that reflect Alterra’s current views with respect to future events and financial performance. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those suggested by such statements. For further information regarding cautionary statements and factors affecting Alterra’s future results, please refer to the most recent reports on Form 10-K and Form 10-Q and other documents filed by Alterra with the SEC. Alterra undertakes no obligation to update or revise publicly any forward-looking statement whether as a result of new information, future developments or otherwise.

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED BALANCE SHEETS

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

	September 30, 2010		December 31, 2009
	(unaudited)
ASSETS
Cash and cash equivalents	$	925,752	$	702,278
Fixed maturities, trading at fair value		243,158		228,696
Fixed maturities, available for sale at fair value		5,425,955		3,007,356
Fixed maturities, held to maturity at amortized cost (fair value $1,106,057)		954,623		1,005,947
Other investments, at fair value		411,275		318,073
Accrued interest income		73,622		57,215
Premiums receivable		664,603		567,301
Losses and benefits recoverable from reinsurers		976,819		1,001,373
Deferred acquisition costs		106,728		65,648
Prepaid reinsurance premiums		173,140		190,613
Trades pending settlement		24,364		76,031
Goodwill and intangible assets		60,670		48,686
Other assets		78,225		70,529
Total assets	$	10,118,934	$	7,339,746
LIABILITIES
Property and casualty losses	$	3,847,366	$	3,178,094
Life and annuity benefits		1,299,190		1,372,513
Deposit liabilities		147,212		152,629
Funds withheld from reinsurers		119,859		140,079
Unearned property and casualty premiums		1,015,831		628,161
Reinsurance balances payable		122,184		146,085
Accounts payable and accrued expenses		90,282		67,088
Senior notes		440,473		90,464
Total liabilities		7,082,397		5,775,113
SHAREHOLDERS’ EQUITY
Preferred shares (par value $1.00) 20,000,000 shares authorized; no shares issued or outstanding		—		—
Common shares (par value $1.00) 200,000,000 shares authorized; 115,898,860 (2009 - 55,867,125) shares issued and outstanding		115,899		55,867
Additional paid-in capital		2,113,732		752,309
Accumulated other comprehensive income		190,325		25,431
Retained earnings		616,581		731,026
Total shareholders’ equity		3,036,537		1,564,633
Total liabilities and shareholders’ equity	$	10,118,934	$	7,339,746
Book value per share	$	26.20	$	28.01
Diluted book value per share	$	25.88	$	27.36
Diluted tangible book value per share [a]	$	25.37	$	26.51
Diluted shares outstanding		117,321,004		57,178,458

[a] Non-Gaap measure as defined by Regulation G.

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited)

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

	Three Months Ended September 30,						Nine Months Ended September 30,
	2010			2009			2010			2009
REVENUES
Gross premiums written	$	325,213		$	265,886		$	1,095,333		$	1,096,668
Reinsurance premiums ceded		(60,611	)		(83,290	)		(293,546	)		(377,338	)
Net premiums written	$	264,602		$	182,596		$	801,787		$	719,330
Earned premiums	$	436,244		$	329,869		$	1,132,964		$	993,871
Earned premiums ceded		(93,812	)		(121,853	)		(303,032	)		(366,788	)
Net premiums earned		342,432			208,016			829,932			627,083
Net investment income		59,711			42,830			161,378			125,073
Net realized and unrealized gains on investments		15,411			24,528			7,047			64,440
Total other-than-temporary impairment losses		(90	)		—			(1,955	)		(5,190	)
Portion of loss recognized in other comprehensive income (loss), before taxes		(61	)		(139	)		1,084			3,037
Net impairment losses recognized in earnings		(151	)		(139	)		(871	)		(2,153	)
Other income		1,327			819			1,946			3,099
Total revenues		418,730			276,054			999,432			817,542
LOSSES AND EXPENSES
Net losses and loss expenses		191,012			131,778			475,794			378,729
Claims and policy benefits		15,060			14,378			46,662			84,117
Acquisition costs		60,859			27,997			133,901			73,686
Interest expense		7,551			5,971			20,409			14,654
Net foreign exchange losses (gains)		3,353			406			267			(6,474	)
Merger and acquisition expenses		550			(41,350	)		(49,276	)		(31,342	)
General and administrative expenses		56,650			40,372			143,827			115,537
Total losses and expenses		335,035			179,552			771,584			628,907
INCOME BEFORE TAXES		83,695			96,502			227,848			188,635
Income tax expense		858			1,176			5,183			5,012
NET INCOME [a]		82,837			95,326			222,665			183,623
Change in net unrealized gains and losses on fixed maturities, net of tax		74,383			95,794			169,039			66,629
Foreign currency translation adjustment		13,224			(4,462	)		(4,145	)		20,372
COMPREHENSIVE INCOME [a]	$	170,444		$	186,658		$	387,559		$	270,624
Basic earnings per share	$	0.71		$	1.67		$	2.52		$	3.22
Diluted earnings per share	$	0.70		$	1.64		$	2.50		$	3.18
Net operating income per diluted share	$	0.64		$	0.92		$	1.97		$	2.57
Weighted average shares outstanding - basic		117,200,505			57,233,115			88,253,609			56,978,901
Weighted average shares outstanding - diluted		117,957,942			58,210,501			89,001,515			57,677,996

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

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY (Unaudited)

(Expressed in thousands of United States Dollars)

	Nine Months Ended September 30
	2010			2009
Common shares
Balance, beginning of period	$	55,867		$	55,806
Issuance of common shares, net		65,084			1,529
Repurchase of shares		(5,052	)		(322	)
Balance, end of period		115,899			57,013
Additional paid-in capital
Balance, beginning of period		752,309			763,391
Issuance of common shares, net		1,418,214			457
Stock based compensation expense		36,600			16,124
Repurchase of shares		(93,391	)		(6,049	)
Balance, end of period		2,113,732			773,923
Accumulated other comprehensive income (loss)
Balance, beginning of period		25,431			(45,399	)
Holding gains on available for sale securities arising in period [a]		179,482			66,650
Net realized (gains) losses on available for sale securities included in net income [a]		(9,359	)		3,016
Portion of other-than-temporary impairment losses recognised in other comprehensive income [a]		(1,084	)		(3,037	)
Foreign currency translation adjustment		(4,145	)		20,372
Balance, end of period		190,325			41,602
Retained earnings
Balance, beginning of period		731,026			506,533
Net income		222,665			183,623
Dividends		(337,110	)		(16,020	)
Balance, end of period		616,581			674,136
Total shareholders’ equity	$	3,036,537		$	1,546,674

[a] Net of tax

ALTERRA CAPITAL HOLDINGS LIMITED

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)

(Expressed in thousands of United States Dollars)

	Nine Months Ended September 30
	2010			2009
OPERATING ACTIVITIES
Net income	$	222,665		$	183,623
Adjustments to reconcile net income to net cash provided by operating activities:
Stock based compensation		36,600			16,124
Amortization of premium on fixed maturities		10,973			2,503
Accretion of deposit liabilities		3,940			2,078
Net realized and unrealized gains on investments		(7,047	)		(64,440	)
Net impairment losses recognized in earnings		871			2,153
Negative goodwill gain		(95,788	)		—
Changes in:
Accrued interest income		(822	)		820
Premiums receivable		266,878			12,894
Losses and benefits recoverable from reinsurers		(9,975	)		(130,985	)
Deferred acquisition costs		(38,485	)		(13,645	)
Prepaid reinsurance premiums		10,865			(11,907	)
Other assets		3,407			(2,624	)
Property and casualty losses		(166,930	)		183,163
Life and annuity benefits		(24,819	)		508
Funds withheld from reinsurers		(20,220	)		(21,773	)
Unearned property and casualty premiums		12,092			92,046
Reinsurance balances payable		(28,025	)		(10,515	)
Accounts payable and accrued expenses		(7,167	)		9,828
Cash provided by operating activities		169,013			249,851
INVESTING ACTIVITIES
Purchases of available for sale securities		(1,752,420	)		(783,451	)
Sales of available for sale securities		892,465			175,465
Redemptions/maturities of available for sale securities		702,506			479,310
Purchases of trading securities		(55,812	)		(40,691	)
Sales of trading securities		14,097			28,887
Redemptions/maturities of trading securities		19,361			5,094
Purchases of held to maturity securities		(16,961	)		(33,647	)
Redemptions/maturities of held to maturity securities		23,599			—
Net purchases/sales of other investments		78,985			462,501
Acquisition of subsidiary, net of cash acquired		446,819			—
Cash provided by investing activities		352,639			293,468
FINANCING ACTIVITIES
Net proceeds from issuance of common shares		1,478			1,986
Repurchase of common shares		(98,443	)		(6,371	)
Net proceeds from issuance of senior notes		349,997			—
Net repayments of bank loans		(200,000	)		(375,000	)
Dividends paid		(335,560	)		(16,020	)
Additions to deposit liabilities		3,453			12,422
Payment of deposit liabilities		(12,747	)		(80,748	)
Cash used in financing activities		(291,822	)		(463,731	)
Effect of exchange rate changes on foreign currency cash and cash equivalents		(6,356	)		27,019
Net increase in cash and cash equivalents		223,474			106,607
Cash and cash equivalents, beginning of period		702,278			949,404
CASH AND CASH EQUIVALENTS, END OF PERIOD	$	925,752		$	1,056,011
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:

Interest paid totaled $5,394 and $4,943 for the nine months ended September 30, 2010 and 2009, respectively.

Income taxes paid totaled $4,068 and $310 for the nine months ended September 30, 2010 and 2009, respectively.

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–THREE MONTHS ENDED SEPTEMBER 30, 2010 (Unaudited)

(Expressed in thousands of United States Dollars)

	Property & Casualty															Life & Annuity
Quarter Segment Information:	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total			Reinsurance			Corporate			Consolidated
Gross premiums written	$	70,271		$	124,004		$	71,871		$	57,734		$	323,880		$	1,333		$	—		$	325,213
Reinsurance premiums ceded		(34,075	)		(2,524	)		(21,513	)		(2,397	)		(60,509	)		(102	)		—			(60,611	)
Net premiums written	$	36,196		$	121,480		$	50,358		$	55,337		$	263,371		$	1,231		$	—		$	264,602
Earned premiums	$	96,777		$	213,510		$	79,200		$	45,424		$	434,911		$	1,333		$	—		$	436,244
Earned premiums ceded		(41,097	)		(15,533	)		(27,770	)		(9,310	)		(93,710	)		(102	)		—			(93,812	)
Net premiums earned		55,680			197,977			51,430			36,114			341,201			1,231			—			342,432
Net investment income		6,209			17,495			1,295			2,256			27,255			12,182			20,274			59,711
Net realized and unrealized gains on investments		188			197			30			883			1,298			3,321			10,792			15,411
Net impairment losses recognized in earnings		—			—			—			—			—			—			(151	)		(151	)
Other income		771			61			337			177			1,346			(43	)		24			1,327
Total revenues		62,848			215,730			53,092			39,430			371,100			16,691			30,939			418,730
Net losses and loss expenses		23,775			117,671			32,199			17,367			191,012			—			—			191,012
Claims and policy benefits		—			—			—			—			—			15,060			—			15,060
Acquisition costs		1,265			45,069			6,880			7,474			60,688			171			—			60,859
Interest expense		80			1,149			—			—			1,229			2,311			4,011			7,551
Net foreign exchange losses (gains)		—			1,478			—			2,089			3,567			—			(214	)		3,353
Merger and acquisition expenses		—			—			—			—			—			—			550			550
General and administrative expenses		6,435			17,580			9,975			7,806			41,796			577			14,277			56,650
Total losses and expenses		31,555			182,947			49,054			34,736			298,292			18,119			18,624			335,035
Income (loss) before taxes	$	31,293		$	32,783		$	4,038		$	4,694		$	72,808		$	(1,428	)	$	12,315		$	83,695
Loss Ratio [a]		42.7	%		59.4	%		62.6	%		48.1	%		56.0	%
Combined Ratio [b]		56.5	%		91.1	%		95.4	%		90.4	%		86.0	%
SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–NINE MONTHS ENDED SEPTEMBER 30, 2010 (Unaudited) (Expressed in thousands of United States Dollars)
	Property & Casualty															Life & Annuity
Year to Date Segment Information [c]:	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total			Reinsurance			Corporate			Consolidated
Gross premiums written	$	269,004		$	398,433		$	246,245		$	178,653		$	1,092,335		$	2,998		$	—		$	1,095,333
Reinsurance premiums ceded		(118,908	)		(61,223	)		(77,592	)		(35,589	)		(293,312	)		(234	)		—			(293,546	)
Net premiums written	$	150,096		$	337,210		$	168,653		$	143,064		$	799,023		$	2,764		$	—		$	801,787
Earned premiums	$	293,692		$	483,982		$	229,122		$	123,170		$	1,129,966		$	2,998		$	—		$	1,132,964
Earned premiums ceded		(132,019	)		(50,545	)		(96,335	)		(23,899	)		(302,798	)		(234	)		—			(303,032	)
Net premiums earned		161,673			433,437			132,787			99,271			827,168			2,764			—			829,932
Net investment income		18,639			42,107			3,951			7,308			72,005			37,701			51,672			161,378
Net realized and unrealized gains (losses) on investments		391			418			29			(583	)		255			7,377			(585	)		7,047
Net impairment losses recognized in earnings		—			—			—			—			—			—			(871	)		(871	)
Other income		760			216			439			528			1,943			(71	)		74			1,946
Total revenues		181,463			476,178			137,206			106,524			901,371			47,771			50,290			999,432
Net losses and loss expenses		96,981			250,177			82,614			46,022			475,794			—			—			475,794
Claims and policy benefits		—			—			—			—			—			46,662			—			46,662
Acquisition costs		1,753			92,708			19,689			19,311			133,461			440			—			133,901
Interest expense		554			6,207			—			—			6,761			6,350			7,298			20,409
Net foreign exchange losses (gains)		—			1,967			—			(1,802	)		165			—			102			267
Merger and acquisition expenses		—			—			—			—			—			—			(49,276	)		(49,276	)
General and administrative expenses		18,833			41,359			26,433			16,345			102,970			1,876			38,981			143,827
Total losses and expenses		118,121			392,418			128,736			79,876			719,151			55,328			(2,895	)		771,584
Income (loss) before taxes	$	63,342		$	83,760		$	8,470		$	26,648		$	182,220		$	(7,557	)	$	53,185		$	227,848
Loss Ratio [a]		60.0	%		57.7	%		62.2	%		46.4	%		57.5	%
Combined Ratio [b]		72.7	%		88.7	%		96.9	%		82.3	%		86.1	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned.

[b] 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.

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

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–THREE MONTHS ENDED SEPTEMBER 30, 2009 (Unaudited)

(Expressed in thousands of United States Dollars)

	Property & Casualty															Life & Annuity
Quarter Segment Information:	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total			Reinsurance			Corporate			Consolidated
Gross premiums written	$	81,134		$	94,118		$	69,419		$	21,087		$	265,758		$	128		$	—		$	265,886
Reinsurance premiums ceded		(41,884	)		(11,106	)		(26,259	)		(4,015	)		(83,264	)		(26	)		—			(83,290	)
Net premiums written	$	39,250		$	83,012		$	43,160		$	17,072		$	182,494		$	102		$	—		$	182,596
Earned premiums	$	103,961		$	128,458		$	68,175		$	29,147		$	329,741		$	128		$	—		$	329,869
Earned premiums ceded		(54,814	)		(25,367	)		(37,074	)		(4,572	)		(121,827	)		(26	)		—			(121,853	)
Net premiums earned		49,147			103,091			31,101			24,575			207,914			102			—			208,016
Net investment income		5,898			10,404			1,461			1,749			19,512			13,143			10,175			42,830
Net realized and unrealized gains on investments		1,298			3,040			—			1,400			5,738			11,932			6,858			24,528
Net impairment losses recognized in earnings		—			—			—			—			—			—			(139	)		(139	)
Other income		91			—			52			(33	)		110			—			709			819
Total revenues		56,434			116,535			32,614			27,691			233,274			25,177			17,603			276,054
Net losses and loss expenses		31,756			68,728			21,266			10,028			131,778			—			—			131,778
Claims and policy benefits		—			—			—			—			—			14,378			—			14,378
Acquisition costs		369			20,299			1,926			5,250			27,844			153			—			27,997
Interest expense		—			1,706			—			—			1,706			2,349			1,916			5,971
Net foreign exchange losses		—			—			—			42			42			—			364			406
Merger and acquisition expenses		—			—			—			—			—			—			(41,350	)		(41,350	)
General and administrative expenses		7,281			8,857			7,804			5,423			29,365			829			10,178			40,372
Total losses and expenses		39,406			99,590			30,996			20,743			190,735			17,709			(28,892	)		179,552
Income before taxes	$	17,028		$	16,945		$	1,618		$	6,948		$	42,539		$	7,468		$	46,495		$	96,502
Loss Ratio [a]		64.6	%		66.7	%		68.4	%		40.8	%		63.4	%
Combined Ratio [b]		80.2	%		94.9	%		99.7	%		84.2	%		90.9	%
SCHEDULE OF SUPPLEMENTAL UNDERWRITING DATA–NINE MONTHS ENDED SEPTEMBER 30, 2009 (Unaudited) (Expressed in thousands of United States Dollars)
	Property & Casualty															Life & Annuity
Year to Date Segment Information:	Insurance			Reinsurance			U.S. Specialty			Alterra at Lloyd’s			Total			Reinsurance			Corporate			Consolidated
Gross premiums written	$	302,727		$	422,296		$	219,268		$	110,629		$	1,054,920		$	41,748		$	—		$	1,096,668
Reinsurance premiums ceded		(146,076	)		(80,574	)		(118,579	)		(31,963	)		(377,192	)		(146	)		—			(377,338	)
Net premiums written	$	156,651		$	341,722		$	100,689		$	78,666		$	677,728		$	41,602		$	—		$	719,330
Earned premiums	$	307,709		$	364,994		$	185,609		$	93,811		$	952,123		$	41,748		$	—		$	993,871
Earned premiums ceded		(157,710	)		(74,711	)		(111,682	)		(22,539	)		(366,642	)		(146	)		—			(366,788	)
Net premiums earned		149,999			290,283			73,927			71,272			585,481			41,602			—			627,083
Net investment income		16,861			29,607			4,549			3,216			54,233			37,626			33,214			125,073
Net realized and unrealized gains on investments		3,537			8,467			148			2,587			14,739			29,146			20,555			64,440
Net impairment losses recognized in earnings		—			—			—			—			—			—			(2,153	)		(2,153	)
Other income		1,238			12			272			475			1,997			—			1,102			3,099
Total revenues		171,635			328,369			78,896			77,550			656,450			108,374			52,718			817,542
Net losses and loss expenses		106,029			192,756			46,500			33,444			378,729			—			—			378,729
Claims and policy benefits		—			—			—			—			—			84,117			—			84,117
Acquisition costs		(1,503	)		53,496			5,873			14,797			72,663			1,023			—			73,686
Interest expense		—			2,400			—			—			2,400			2,803			9,451			14,654
Net foreign exchange gains		—			—			—			(5,124	)		(5,124	)		—			(1,350	)		(6,474	)
Merger and acquisition expenses		—			—			—			—			—			—			(31,342	)		(31,342	)
General and administrative expenses		17,825			23,604			21,195			15,856			78,480			2,180			34,877			115,537
Total losses and expenses		122,351			272,256			73,568			58,973			527,148			90,123			11,636			628,907
Income before taxes	$	49,284		$	56,113		$	5,328		$	18,577		$	129,302		$	18,251		$	41,082		$	188,635
Loss Ratio [a]		70.7	%		66.4	%		62.9	%		46.9	%		64.7	%
Combined Ratio [b]		81.6	%		93.0	%		99.5	%		89.9	%		90.5	%

[a] The loss ratio is calculated by dividing net losses and loss expenses by net premiums earned.

[b] 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.

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL PREMIUM DATA–NINE MONTHS ENDED SEPTEMBER 30, 2010 (Unaudited)

(Expressed in thousands of United States Dollars)

		Nine Months Ended September 30, 2010					Movement on Prior Year Period			Nine Months Ended September 30, 2009
Gross Premiums Written by Type of Risk:		Gross Premiums Written		Percentage of Total Gross Premiums Written						Gross Premiums Written		Percentage of Total Gross Premiums Written
Property & Casualty:
Insurance:
Aviation	S	$	17,211		1.6	%		(43.2	%)	$	30,314		2.8	%
Excess Liability	L		71,230		6.5	%		(18.2	%)		87,084		7.9	%
Professional Liability	L		129,462		11.8	%		(4.0	%)		134,845		12.3	%
Property	S		51,101		4.7	%		1.2	%		50,484		4.6	%
			269,004		24.6	%		(11.1	%)		302,727		27.6	%
Reinsurance [a]:
Agriculture	S		30,628		2.8	%		(64.9	%)		87,338		8.0	%
Auto	S		10,317		0.9	%		n/a			—		—
Aviation	S		28,696		2.6	%		13.3	%		25,335		2.3	%
Credit/ Surety	L		1,078		0.1	%		n/a			—		—
General Casualty	L		30,699		2.8	%		31.2	%		23,404		2.1	%
Marine & Energy	S		17,930		1.6	%		21.8	%		14,722		1.3	%
Medical Malpractice	L		31,837		3.0	%		(43.5	%)		56,397		5.1	%
Other	S		2,264		0.2	%		(0.2	%)		2,268		0.2	%
Professional Liability	L		81,889		7.5	%		78.3	%		45,922		4.2	%
Property	S		141,850		13.0	%		58.6	%		89,414		8.2	%
Whole Account	S/L		4,703		0.4	%		(44.7	%)		8,509		0.8	%
Workers’ Compensation	L		16,542		1.5	%		(76.0	%)		68,987		6.3	%
			398,433		36.4	%		(5.7	%)		422,296		38.5	%
U.S. Specialty:
General Liability	L		76,205		7.0	%		10.4	%		69,026		6.3	%
Marine	S		49,696		4.5	%		8.2	%		45,917		4.2	%
Professional Liability	L		9,526		0.8	%		n/a			—		—
Property	S		110,818		10.1	%		6.2	%		104,325		9.5	%
			246,245		22.4	%		12.3	%		219,268		20.0	%
Alterra at Lloyd’s:
Accident & Health	S		25,351		2.3	%		18.7	%		21,357		2.0	%
Aviation	S		10,914		1.0	%		n/a			—		—
Financial Institutions	L		19,064		1.7	%		3.7	%		18,376		1.7	%
International Casualty	L		28,330		2.6	%		n/a			—		—
Professional Liability	L		15,387		1.4	%		5.4	%		14,599		1.3	%
Property	S		79,607		7.3	%		41.4	%		56,297		5.1	%
			178,653		16.3	%		61.5	%		110,629		10.1	%
Aggregate Property & Casualty		$	1,092,335		99.7	%		3.5	%	$	1,054,920		96.2	%
Life & Annuity:
Annuity		$	6		0.0	%		n/a		$	—		—
Life			2,992		0.3	%		(92.8	%)		41,748		3.8	%
Aggregate Life & Annuity		$	2,998		0.3	%		(92.8	%)	$	41,748		3.8	%
Aggregate Property & Casualty and Life & Annuity		$	1,095,333		100.0	%		(0.1	%)	$	1,096,668		100.0	%
S = Short tail lines		$	578,735		53.0	%				$	532,026		50.4	%
L = Long tail lines			513,600		47.0	%					522,894		49.6	%
Aggregate Property & Casualty		$	1,092,335							$	1,054,920

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

ALTERRA CAPITAL HOLDINGS LIMITED

NON-GAAP FINANCIAL MEASURE RECONCILIATIONS (Unaudited)

Net Operating Income and Net Operating Income per Diluted Share

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

	Three Months Ended September 30,						Nine Months Ended September 30,
	2010			2009			2010			2009
Net income before tax	$	83,695		$	96,502		$	227,848		$	188,635
Net realized and unrealized (gains) losses on non-hedge fund investments, before tax [a]		(10,440	)		(1,189	)		2,692			(109	)
Foreign exchange losses (gains), before tax		3,353			406			267			(6,474	)
Merger and acquisition expenses, before tax		550			(41,350	)		(49,276	)		(31,342	)
Net operating income before tax	$	77,158		$	54,369		$	181,531		$	150,710
Net income	$	82,837		$	95,326		$	222,665		$	183,623
Net realized and unrealized (gains) losses on non-hedge fund investments, net of tax [a]		(10,104	)		(711	)		2,672			1,166
Foreign exchange losses (gains), net of tax		2,758			395			780			(5,043	)
Merger and acquisition expenses, net of tax		550			(41,350	)		(50,621	)		(31,342	)
Net operating income	$	76,041		$	53,660		$	175,496		$	148,404
Net income per diluted share	$	0.70		$	1.64		$	2.50		$	3.18
Net realized and unrealized (gains) losses on non-hedge fund investments, net of tax [a]		(0.08	)		(0.01	)		0.03			0.02
Foreign exchange losses (gains), net of tax		0.02			0.01			0.01			(0.09	)
Merger and acquisition expenses, net of tax		—			(0.72	)		(0.57	)		(0.54	)
Net operating income per diluted share	$	0.64		$	0.92		$	1.97		$	2.57
Weighted average shares outstanding - basic		117,200,505			57,233,115			88,253,609			56,978,901
Weighted average shares outstanding - diluted		117,957,942			58,210,501			89,001,515			57,677,996

[a] Net realized and unrealized (gains) losses on non-hedge fund investments includes realized and unrealized (gains) losses on trading securities, realised (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.

Annualized Net Operating Return on Average Shareholders’ Equity

(Expressed in thousands of United States Dollars)

	Three Months Ended September 30,						Nine Months Ended September 30,
	2010			2009			2010			2009
Net income	$	82,837		$	95,326		$	222,665		$	183,623
Annualized net income		331,348			381,304			296,887			244,831
Net operating income	$	76,041		$	53,660		$	175,496		$	148,404
Annualized net operating income		304,164			214,640			233,995			197,872
Average shareholders’ equity [b]	$	2,981,752		$	1,455,072		$	2,297,438		$	1,346,611
Annualized return on average shareholders’ equity		11.1	%		26.2	%		12.9	%		18.2	%
Annualized net operating return on average shareholders’ equity		10.2	%		14.8	%		10.2	%		14.7	%

[b] Average shareholders’ equity is computed as the average of the quarterly shareholders’ equity balances. The average for the nine months ended September 30, 2010 has been weighted to include Harbor Point Limited from May 12, 2010.

Diluted Tangible Book Value Per Share

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

	September 30, 2010			December 31, 2009
Shareholders’ equity	$	3,036,537		$	1,564,633
Goodwill and intangible assets		(60,670	)		(48,686	)
Tangible book value	$	2,975,867		$	1,515,947
Diluted shares outstanding		117,321,004			57,178,458
Diluted tangible book value per share	$	25.37		$	26.51

ALTERRA CAPITAL HOLDINGS LIMITED

SCHEDULE OF SUPPLEMENTAL INVESTMENT DATA–SEPTEMBER 30, 2010 (Unaudited)

(Expressed in thousands of United States Dollars)

Type of Investment	As of September 30, 2010		Investment Distribution			As of December 31, 2009		Investment Distribution
Cash and cash equivalents	$	925,752		11.6	%	$	702,278		13.4	%
U.S. government and agencies		1,049,245		13.2	%		525,427		10.0	%
Non-U.S. governments		81,878		1.0	%		82,027		1.5	%
Corporate securities		2,766,645		34.7	%		1,375,999		26.2	%
Municipal securities		226,946		2.9	%		83,658		1.6	%
Asset-backed securities		82,982		1.0	%		102,006		1.9	%
Residential mortgage-backed securities		1,112,602		14.0	%		763,974		14.5	%
Commercial mortgage-backed securities		348,815		4.4	%		302,961		5.8	%
Fixed maturities at fair value	$	5,669,113		71.2	%	$	3,236,052		61.5	%
U.S. government and agencies	$	22,690		0.3	%	$	14,050		0.3	%
Non-U.S. governments		549,238		6.9	%		573,250		10.9	%
Corporate securities		381,695		4.8	%		418,647		7.9	%
Asset-backed securities		1,000		0.0	%		—		0.0	%
Fixed maturities at amortized cost	$	954,623		12.0	%	$	1,005,947		19.1	%
Other investments	$	411,275		5.2	%	$	318,073		6.0	%
Total invested assets	$	7,960,763		100.0	%	$	5,262,350		100.0	%
Credit Rating	As of September  30, 2010		Ratings Distribution			As of December  31, 2009		Ratings Distribution
U.S. government and agencies [a]	$	2,064,495		31.2	%	$	1,214,895		28.6	%
AAA		1,155,082		17.4	%		720,364		17.0	%
AA		634,250		9.6	%		325,997		7.7	%
A		1,364,226		20.6	%		731,723		17.3	%
BBB		227,276		3.4	%		100,841		2.4	%
BB		33,378		0.5	%		34,781		0.8	%
B or lower		190,406		2.9	%		107,451		2.5	%
Fixed maturities at fair value	$	5,669,113		85.6	%	$	3,236,052		76.3	%
U.S. government and agencies	$	22,690		0.3	%	$	14,050		0.3	%
AAA		654,700		9.9	%		717,954		16.9	%
AA		113,634		1.7	%		101,675		2.4	%
A		149,422		2.3	%		158,141		3.7	%
BBB		12,749		0.2	%		12,672		0.3	%
BB		—		—			—		—
B or lower		1,428		0.0	%		1,455		0.1	%
Fixed maturities at amortized cost	$	954,623		14.4	%	$	1,005,947		23.7	%
Total fixed maturities	$	6,623,736		100.0	%	$	4,241,999		100.0	%

[a] Included within U.S. government and agencies are agency-issued residential mortgage-backed securities with a fair value of $1,015,250 (December 31, 2009: $689,468)

	Three Months Ended September 30,						Nine Months Ended September 30,
	2010			2009			2010			2009
Net investment income	$	59,711		$	42,830		$	161,378		$	125,073
Realized and unrealized gains (losses) on trading fixed maturities		883			1,400			(583	)		2,587
Net realized gains (losses) on available for sale fixed maturities		6,395			(655	)		9,658			(1,348	)
Change in fair value of hedge funds		4,820			23,200			8,868			62,178
Change in fair value of non-hedge fund other investments		3,313			583			(10,896	)		1,023
Net realized and unrealized gains on investments	$	15,411		$	24,528		$	7,047		$	64,440
Net impairment losses recognized in earnings	$	(151	)	$	(139	)	$	(871	)	$	(2,153	)

Contacts
Susan Spivak Bernstein Senior Vice President susan.spivak@alterra-bm.com 1-212-898-6640	Roanne Kulakoff or Peter Hill Kekst and Company roanne-kulakoff@kekst.com peter-hill@kekst.com 1-212-521-4800