Exhibit 99.1

FOR IMMEDIATE RELEASE

ALLIED WORLD REPORTS RECORD NET INCOME OF $665 MILLION IN 2010;
GROWS BOOK VALUE PER SHARE BY 25% FOR YEAR

ZUG, SWITZERLAND, February 17, 2011 — Allied World Assurance Company Holdings, AG (NYSE: AWH) today reported record net income of $665.0 million, or $13.32 per diluted share, for the year ended December 31, 2010 compared to net income of $606.9 million, or $11.67 per diluted share, for the year ended December 31, 2009. Net income for the fourth quarter of 2010 was $92.8 million, or $2.13 per diluted share, compared to net income of $161.3 million, or $3.05 per diluted share, for the fourth quarter of 2009.

The company reported operating income of $397.8 million, or $7.97 per diluted share, for the year ended December 31, 2010 compared to operating income of $537.7 million, or $10.34 per diluted share, for the year ended December 31, 2009. Operating income for the fourth quarter of 2010 was $97.3 million, or $2.24 per diluted share, compared to operating income of $131.9 million, or $2.49 per diluted share, for the fourth quarter of 2009.

President and Chief Executive Officer Scott Carmilani commented, “The insurance industry continued to face significant hurdles throughout 2010. In addition to the heightened rate pressure caused by strong competition and an overabundance of capacity, multiple global catastrophes increased loss costs while generally weak economic conditions posed additional challenges. In spite of these factors, we are very proud of our financial, strategic and operational accomplishments throughout the year.”

“We grew book value per share by 25% producing a record net income of $665 million for the year. Just as importantly, we’ve improved our positioning for the future by redomiciling our holding company to Switzerland, establishing our own Lloyd’s Syndicate 2232 for broader distribution, and further diversifying our products and service capabilities, while lowering our dependence on more volatile segments of the market. In aggregate, these initiatives have helped us generate $197 million in gross revenues from new products and geographies that allowed us to modestly increase our gross premiums written by 4% for the year.”

Mr. Carmilani continued, “We were also very successful on the capital management front during 2010 as we took advantage of our depressed valuation position and deployed significant excess capital to the benefit of our shareholders. We further enhanced our capital flexibility during the fourth quarter through the issuance of $300 million of senior notes, which were at a very favorable interest rate and very well received by the fixed income market. The company begins 2011 in a strong capital position, which provides security to our current policyholders while leaving us with the flexibility to pursue additional potential opportunities for profitable growth.”

Underwriting Results

Gross premiums written were $381.9 million in the fourth quarter of 2010, an 18.6% increase compared to $322.1 million in the fourth quarter of 2009. For the year ended December 31, 2010, gross premiums written totaled $1,758.4 million, a 3.7% increase compared to $1,696.3 million for the year ended December 31, 2009. Net premiums written were $287.2 million in the fourth quarter of 2010, a 22.9% increase compared to $233.7 million in the fourth quarter of 2009. For the year ended December 31, 2010, net premiums written totaled $1,392.5 million, a 5.4% increase compared to $1,321.1 million for the year ended December 31, 2009. These increases were primarily due to the expansion of our reinsurance and U.S. insurance business offset by our selectively paring back general property, energy and professional liability risks in our international insurance segment that did not meet our underwriting requirements.

Net premiums earned in the fourth quarter of 2010 were $342.8 million, a 3.7% increase compared to $330.5 million in the fourth quarter of 2009. For the year ended December 31, 2010, net premiums earned totaled $1,359.5 million, a 3.2% increase from net premiums earned of $1,316.9 million for the year ended December 31, 2009. These increases were primarily due to the expansion of our reinsurance and U.S. insurance business.

The combined ratio was 82.8% in the fourth quarter of 2010 compared to 76.2% in the fourth quarter of 2009. The loss and loss expense ratio was 46.7% in the fourth quarter of 2010 compared to 42.8% in the fourth quarter of 2009. During the fourth quarter of 2010, the company recorded net favorable reserve development on prior loss years of $73.9 million, a benefit of 21.6 percentage points to the company’s loss and loss expense ratio for the quarter. This compares to the fourth quarter of 2009, where the company recorded net favorable reserve development on prior loss years of $77.7 million, a benefit of 23.5 percentage points to the company’s loss and loss expense ratio for that quarter. Absent prior year

reserve adjustments, the loss and loss expense ratio related to the fourth quarter of 2010 was 68.3% compared to 66.3% for the fourth quarter of 2009. The fourth quarter 2010 ratio was impacted by $21.4 million of net losses, or 6.2 percentage points, from major loss driven events occurring during 2010.

For the year ended December 31, 2010, the combined ratio was 84.9% compared to 76.1% for the year ended December 31, 2009. For the year ended December 31, 2010, the company recorded net favorable reserve development on prior loss years of $313.3 million, a benefit of 23.1 percentage points to the company’s loss and loss expense ratio. For the year ended December 31, 2009, the company recorded net favorable reserve development on prior loss years of $248.0 million, a benefit of 18.8 percentage points to the company’s loss and loss expense ratio. Absent prior year reserve adjustments, the loss and loss expense ratio related to 2010 was 75.2% compared to 64.7% for 2009. This ratio was impacted by $164.6 million of net losses, or 12.1 percentage points, from major loss driven events occurring during 2010.

The company’s expense ratio was 36.1% for the fourth quarter of 2010 compared to 33.4% for the fourth quarter of 2009. The expense ratio was 32.8% for the year ended December 31, 2010 compared to 30.2% for the year ended December 31, 2009. Included in our expenses are significant one-time expenses incurred in connection with our redomestication to Switzerland, the establishment of our new Lloyd’s syndicate, as well as an increase in our incentive compensation expenses as a result of our exceeding our compensation targets. Without these items our expense ratio for the fourth quarter of 2010 would have been 33.4%.

Investment Results

The total return on the company’s investment portfolio for the three months and year ended December 31, 2010 was a loss of 0.2% and gain of 6.1%, respectively. Net investment income in the fourth quarter of 2010 was $50.2 million, a decrease of 31.5% from the $73.3 million of net investment income in the fourth quarter of 2009. For the year ended December 31, 2010, net investment income was $244.1 million, a decrease of 18.8% from the $300.7 million of net investment income for the year ended December 31, 2009. These decreases were due to a combination of use of funds for share repurchases, lower yields on our fixed maturity investments and an increased allocation to hedge funds, which contribute to our total return but carry no current yield. The book yield for the year ended December 31, 2010 was 3.3%, versus the annualized book yield for the year ended December 31, 2009 of 4.2%.

The company recorded net realized investment losses of $3.7 million and net realized investment gains of $285.6 million, respectively, for the three months and year ended December 31, 2010.

As of December 31, 2010 and December 31, 2009, net accumulated unrealized gains were $57.1 million and $149.8 million, respectively.

Shareholders’ Equity

As of December 31, 2010, shareholders’ equity was $3.1 billion, a decrease of 4.3% compared to $3.2 billion reported as of December 31, 2009. The decrease was primarily the result of our share repurchase activities during the year partially offset by net income for the year ended December 31, 2010 of $665.0 million, driven primarily by strong investment returns.

The company’s annualized net income return on average shareholders’ equity for the three months and year ended December 31, 2010 was 11.9% and 21.9%, respectively. The company’s annualized operating return on average shareholders’ equity for the three months and year ended December 31, 2010 was 12.5% and 13.1%, respectively.

Share Repurchases

As of December 31, 2010, diluted book value per share was $74.29, an increase of 2.6% and 24.7% compared to $72.40 and $59.56, respectively, as of September 30, 2010 and December 31, 2009.

In May 2010, the company announced a share repurchase program. During the fourth quarter 2010, the company repurchased 1,251,953 of its common shares in the open market at an average repurchase price of $59.20 per share for an aggregate cost of $74.1 million. For the year ended December 31, 2010, the company repurchased 4,651,279 of its common shares through its program in the open market at an average repurchase price of $51.41 per share for an aggregate cost of $239.1 million.

On November 6, 2010, the company repurchased the remainder of securities held by certain GS Capital Partners and other investment funds, which are affiliates of The Goldman Sachs Group, Inc (“Goldman Sachs”), and founding shareholders of our company. These securities consist of 3,159,793 common shares and warrants to purchase an additional 1,500,000

common shares from Goldman Sachs. The aggregate repurchase price for these securities was $222.6 million. The transaction was funded using available cash on hand and was executed separately from the company’s share repurchase program.

Through December 31, 2010, the share repurchases related to our share repurchase program and repurchases from the affiliates of Goldman Sachs have had an estimated $5.11 net accretive impact on diluted book value per share.

On February 3, 2011, the company repurchased a warrant owned by American International Group, Inc. (“AIG”), a founding shareholder, which entitled AIG to purchase a total of 2,000,000 common shares. The aggregate repurchase price was $53.6 million. The transaction was funded using available cash on hand and was executed separately from the company’s share repurchase program.

Quarterly Dividend

On November 26, 2010, the board of directors declared a special dividend of $0.25 per common share related to the company’s redomestication to Switzerland. This special dividend was paid on November 26, 2010 to shareholders of record on November 15, 2010. Under Swiss law, the company will not be able to pay another dividend until two months after the company’s next annual meeting which is expected to take place in early May 2011. This special dividend provided a dividend to shareholders for the interim period until the next dividend can be paid.

Investment Supplement

Allied World will be providing additional information on its investment portfolio as of December 31, 2010. This information will be available at the “Investor Relations” section of the company’s website at www.awac.com.

Financial Supplement

A financial supplement relating to the fourth quarter of 2010 will be available at the “Investor Relations” section of the company’s website at www.awac.com.

Conference Call

Allied World will host a conference call on Friday, February 18, 2011 at 9:00 a.m. (Eastern Time) to discuss the results for the fourth quarter and year ended December 31, 2010. The public may access a live webcast of the conference call at the “Investor Relations” section of the company’s website at www.awac.com. In addition, the conference call can be accessed by dialing (877) 317-6701 (U.S. and Canada callers) or (412) 317-6701 (international callers) and entering the passcode 8832831 approximately ten minutes prior to the call.

Following the conclusion of the presentation, a replay of the call will be available through Friday, March 4, 2011 by dialing (877) 344-7529 (U.S. and Canada callers) or (412) 317-0088 (international callers) and entering the passcode 447223. In addition, the webcast will remain available online through Friday, March 4, 2011 at www.awac.com.

Non-GAAP Financial Measures

In presenting the company’s results, management has included and discussed in this press release certain non-generally accepted accounting principles (“non-GAAP”) financial measures within the meaning of Regulation G as promulgated by the U.S. Securities and Exchange Commission. Management believes that these non-GAAP measures, which may be defined differently by other companies, better explain the company’s results of operations in a manner that allows for a more complete understanding of the underlying trends in the company’s business. However, these measures should not be viewed as a substitute for those determined in accordance with generally accepted accounting principles (“U.S. GAAP”).

“Operating income” is an internal performance measure used in the management of the company’s operations and represents after-tax operational results excluding, as applicable, net realized investment gains or losses, net impairment charges recognized in earnings, impairment of intangible assets and foreign exchange gain or loss. The company excludes net realized investment gains or losses, net impairment charges recognized in earnings and net foreign exchange gain or loss from the calculation of operating income because the amount of these gains or losses is heavily influenced by and fluctuates in part according to the availability of market opportunities and other factors. The company excludes impairment of intangible assets as these are non-recurring charges. In addition to presenting net income determined in accordance with U.S. GAAP, the company believes that showing operating income enables investors, analysts, rating agencies and other users of the company’s financial information to more easily analyze our results of operations and underlying business performance. Operating income should not be viewed as a substitute for U.S. GAAP net income.

The company has included “diluted book value per share” because it takes into account the effect of dilutive securities; therefore, the company believes it is an important measure of calculating shareholder returns.

“Annualized net income return on average shareholders’ equity” (“ROAE”) is calculated using average shareholders’ equity, excluding the average after tax unrealized gains (or losses) on investments. Unrealized gains (losses) on investments are primarily the result of interest rate and credit spread movements and the resultant impact on fixed income securities. Such gains (losses) are not related to management actions or operational performance, nor are they likely to be realized. Therefore, the company believes that excluding these unrealized gains (losses) provides a more consistent and useful measurement of operating performance, which supplements U.S. GAAP information. In calculating ROAE, the net income (loss) available to shareholders for the period is multiplied by the number of such periods in a calendar year in order to arrive at annualized net income (loss) available to shareholders. The company presents ROAE as a measure that is commonly recognized as a standard of performance by investors, analysts, rating agencies and other users of its financial information.

“Annualized operating return on average shareholders’ equity” is calculated using operating income (as defined above and annualized in the manner described for net income (loss) available to shareholders under ROAE above), and average shareholders’ equity, excluding the average after tax unrealized gains (losses) on investments. Unrealized gains (losses) are excluded from equity for the reasons outlined in the annualized net income return on average shareholders’ equity explanation above.

Reconciliations of these financial measures to their most directly comparable U.S. GAAP measures are included in the attached tables.

About Allied World Assurance Company

Allied World Assurance Company Holdings, AG, through its subsidiaries, is a global provider of innovative property, casualty and specialty insurance and reinsurance solutions, offering superior client service through a global network of branches and affiliates. Our insurance and reinsurance subsidiaries are rated A (Excellent) by A.M. Best Company, and our Lloyd’s Syndicate 2232 is rated A+ (Strong) by Standard & Poor’s and Fitch. Please visit our website at www.awac.com for further information on Allied World.

Cautionary Statement Regarding Forward-Looking Statements

Any forward-looking statements made in this press release reflect our current views with respect to future events and financial performance and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements involve risks and uncertainties, which may cause actual results to differ materially from those set forth in these statements. For example, our forward-looking statements could be affected by pricing and policy term trends; increased competition; the impact of acts of terrorism and acts of war; greater frequency or severity of unpredictable catastrophic events; negative rating agency actions; the adequacy of our loss reserves; the company or its subsidiaries becoming subject to significant income taxes in the United States or elsewhere; changes in regulations or tax laws; changes in the availability, cost or quality of reinsurance or retrocessional coverage; adverse general economic conditions; and judicial, legislative, political and other governmental developments, as well as management’s response to these factors, and other factors identified in our filings with the U.S. Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date on which they are made. We are under no obligation (and expressly disclaim any such obligation) to update or revise any forward-looking statement that may be made from time to time, whether as a result of new information, future developments or otherwise.

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
(Expressed in thousands of United States dollars, except share and per share amounts)

		Quarter Ended December 31,								Year Ended December 31,
		2010				2009				2010				2009
Revenues:
Gross premiums written		$	381,942			$	322,129			$	1,758,397			$	1,696,345
Premiums ceded			(94,743	)			(88,435	)			(365,942	)			(375,220	)
Net premiums written			287,199				233,694				1,392,455				1,321,125
Change in unearned premiums			55,605				96,787				(32,907	)			(4,233	)
Net premiums earned			342,804				330,481				1,359,548				1,316,892
Net investment income			50,168				73,252				244,143				300,675
Net realized investment (losses) gains			(3,738	)			37,796				285,612				126,352
Net impairment charges recognized in earnings			—				(187	)			(168	)			(49,577	)
Other income			—				373				913				1,506
Total revenue			389,234				441,715				1,890,048				1,695,848
Expenses:
Net losses and loss expenses			160,019				141,403				707,883				604,060
Acquisition costs			38,848				38,126				159,489				148,847
General and administrative expenses			85,134				72,212				286,557				248,592
Amortization and impairment of intangible assets			808				7,856				3,483				11,051
Interest expense			11,650				9,527				40,242				39,019
Foreign exchange loss			196				1,408				444				748
Total expenses			296,655				270,532				1,198,098				1,052,317
Income before income taxes			92,579				171,183				691,950				643,531
Income tax (benefit) expense			(207	)			9,928				26,945				36,644
NET INCOME		$	92,786			$	161,255			$	665,005			$	606,887
PER SHARE DATA:
Basic earnings per share		$	2.30			$	3.25			$	14.30			$	12.26
Diluted earnings per share		$	2.13			$	3.05			$	13.32			$	11.67
Weighted average common shares outstanding			40,291,620				49,662,575				46,491,279				49,503,438
Weighted average common shares and common share equivalents outstanding			43,501,068				52,880,733				49,913,317				51,992,674
Dividends declared per share		$	0.45			$	0.20			$	1.05			$	0.74

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS
(Expressed in thousands of United States dollars, except share and per share amounts)

		As of				As of
		December 31,				December 31,
		2010				2009
ASSETS:
Fixed maturity investments available for sale, at fair value (amortized cost: 2010: $828,544; 2009: $4,260,844)		$	891,849			$	4,427,072
Fixed maturity investments trading, at fair value			5,769,097				2,544,322
Other invested assets trading, at fair value			522,608				184,869
Total investments			7,183,554				7,156,263
Cash and cash equivalents			853,368				379,751
Insurance balances receivable			529,927				395,621
Prepaid reinsurance			187,287				186,610
Reinsurance recoverable			927,588				919,991
Accrued investment income			40,520				53,046
Net deferred acquisition costs			96,803				87,821
Goodwill			268,376				268,376
Intangible assets			56,876				60,359
Net balances receivable on purchases and sales of investments			—				184
Net deferred tax assets			19,740				21,895
Other assets			75,184				67,566
Total assets		$	10,239,223			$	9,597,483
LIABILITIES:
Reserve for losses and loss expenses		$	4,879,188			$	4,761,772
Unearned premiums			962,203				928,619
Reinsurance balances payable			99,732				102,837
Net balances payable on purchases and sales of investments			318,570				—
Senior notes			797,700				498,919
Accounts payable and accrued liabilities			106,010				92,041
Total liabilities		$	7,163,403			$	6,384,188
SHAREHOLDERS’ EQUITY:
Common shares, 2010: par value CHF 15.00 per share; 2009: par value $0.03 per share (2010: 40,003,642; 2009: 49,734,487 shares issued and 2010: 38,089,226; 2009: 49,734,487 shares outstanding)			600,055				1,492
Additional paid-in capital			170,239				1,359,934
Treasury shares, at cost (2010: 1,914,416, 2009: nil)			(112,811	)			—
Retained earnings			2,361,202				1,702,020
Accumulated other comprehensive income, net of tax			57,135				149,849
Total shareholders’ equity			3,075,820				3,213,295
Total liabilities and shareholders’ equity		$	10,239,223			$	9,597,483

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED CONSOLIDATED SEGMENT DATA
(Expressed in thousands of United States dollars, except for ratio information)

		U.S.				International
Quarter Ended December 31, 2010		Insurance				Insurance				Reinsurance				Total
Gross premiums written		$	196,287			$	115,056			$	70,599			$	381,942
Net premiums written			143,789				73,973				69,437				287,199
Net premiums earned			133,930				81,764				127,110				342,804
Other income			—				—				—				—
Net losses and loss expenses			(74,750	)			(27,084	)			(58,185	)			(160,019	)
Acquisition costs			(16,902	)			431				(22,377	)			(38,848	)
General and administrative expenses			(38,978	)			(26,905	)			(19,251	)			(85,134	)
Underwriting income			3,300				28,206				27,297				58,803
Net investment income															50,168
Net realized investment losses															(3,738	)
Net impairment charges recognized in earnings															—
Amortization and impairment of intangible assets															(808	)
Interest expense															(11,650	)
Foreign exchange loss															(196	)
Income before income taxes														$	92,579
GAAP Ratios:
Loss and loss expense ratio			55.8	%			33.1	%			45.8	%			46.7	%
Acquisition cost ratio			12.6	%			(0.5	%)			17.6	%			11.3	%
General and administrative expense ratio			29.1	%			32.9	%			15.1	%			24.8	%
Combined ratio			97.5	%			65.5	%			78.5	%			82.8	%

		U.S.				International
Quarter Ended December 31, 2009		Insurance				Insurance				Reinsurance				Total
Gross premiums written		$	169,116			$	130,272			$	22,741			$	322,129
Net premiums written			123,155				87,827				22,712				233,694
Net premiums earned			119,641				92,464				118,376				330,481
Other income			373				—				—				373
Net losses and loss expenses			(68,273	)			(16,467	)			(56,663	)			(141,403	)
Acquisition costs			(15,806	)			501				(22,821	)			(38,126	)
General and administrative expenses			(32,474	)			(25,791	)			(13,947	)			(72,212	)
Underwriting income			3,461				50,707				24,945				79,113
Net investment income															73,252
Net realized investment gains															37,796
Net impairment charges recognized in earnings															(187	)
Amortization and impairment of intangible assets															(7,856	)
Interest expense															(9,527	)
Foreign exchange loss															(1,408	)
Income before income taxes														$	171,183
GAAP Ratios:
Loss and loss expense ratio			57.1	%			17.8	%			47.9	%			42.8	%
Acquisition cost ratio			13.2	%			(0.5	%)			19.3	%			11.5	%
General and administrative expense ratio			27.1	%			27.9	%			11.8	%			21.9	%
Combined ratio			97.4	%			45.2	%			79.0	%			76.2	%

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED CONSOLIDATED SEGMENT DATA
(Expressed in thousands of United States dollars, except for ratio information)

		U.S.				International
Year Ended December 31, 2010		Insurance				Insurance				Reinsurance				Total
Gross premiums written		$	729,267			$	504,937			$	524,193			$	1,758,397
Net premiums written			551,063				319,083				522,309				1,392,455
Net premiums earned			518,444				338,791				502,313				1,359,548
Other income			913				—				—				913
Net losses and loss expenses			(297,517	)			(160,153	)			(250,213	)			(707,883	)
Acquisition costs			(67,797	)			460				(92,152	)			(159,489	)
General and administrative expenses			(128,556	)			(94,226	)			(63,775	)			(286,557	)
Underwriting income			25,487				84,872				96,173				206,532
Net investment income															244,143
Net realized investment gains															285,612
Net impairment charges recognized in earnings															(168	)
Amortization and impairment of intangible assets															(3,483	)
Interest expense															(40,242	)
Foreign exchange loss															(444	)
Income before income taxes														$	691,950
GAAP Ratios:
Loss and loss expense ratio			57.4	%			47.3	%			49.8	%			52.1	%
Acquisition cost ratio			13.1	%			(0.1	%)			18.3	%			11.7	%
General and administrative expense ratio			24.8	%			27.8	%			12.7	%			21.1	%
Combined ratio			95.3	%			75.0	%			80.8	%			84.9	%

		U.S.				International
Year Ended December 31, 2009		Insurance				Insurance				Reinsurance				Total
Gross premiums written		$	674,826			$	555,944			$	465,575			$	1,696,345
Net premiums written			493,067				362,893				465,165				1,321,125
Net premiums earned			447,491				413,170				456,231				1,316,892
Other income			1,506				—				—				1,506
Net losses and loss expenses			(211,363	)			(158,062	)			(234,635	)			(604,060	)
Acquisition costs			(58,114	)			(2,742	)			(87,991	)			(148,847	)
General and administrative expenses			(115,797	)			(84,390	)			(48,405	)			(248,592	)
Underwriting income			63,723				167,976				85,200				316,899
Net investment income															300,675
Net realized investment gains															126,352
Net impairment charges recognized in earnings															(49,577	)
Amortization and impairment of intangible assets															(11,051	)
Interest expense															(39,019	)
Foreign exchange loss															(748	)
Income before income taxes														$	643,531
GAAP Ratios:
Loss and loss expense ratio			47.2	%			38.3	%			51.4	%			45.9	%
Acquisition cost ratio			13.0	%			0.7	%			19.3	%			11.3	%
General and administrative expense ratio			25.9	%			20.4	%			10.6	%			18.9	%
Combined ratio			86.1	%			59.4	%			81.3	%			76.1	%

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED OPERATING INCOME RECONCILIATION
(Expressed in thousands of United States dollars, except share and per share amounts)

		Quarter Ended December 31,								Year Ended December 31
		2010				2009				2010				2009
Net income		$	92,786			$	161,255			$	665,005			$	606,887
Add after tax affect of:
Net realized investment (losses) gains			4,306				(37,796	)			(267,727	)			(126,352	)
Net impairment charges recognized in earnings			—				187				109				49,577
Impairment of intangible assets			—				6,866				—				6,866
Foreign exchange loss			196				1,408				444				748
Operating income		$	97,288			$	131,920			$	397,831			$	537,726
Weighted average common shares outstanding:
Basic			40,291,620				49,662,575				46,491,279				49,503,438
Diluted			43,501,068				52,880,733				49,913,317				51,992,674
Basic per share data:
Net income		$	2.30			$	3.25			$	14.30			$	12.26
Add after tax affect of:
Net realized investment (losses) gains			0.11				(0.76	)			(5.75	)			(2.55	)
Net impairment charges recognized in earnings			—				—				—				1.00
Impairment of intangible assets			—				0.14				—				0.14
Foreign exchange loss			—				0.03				0.01				0.01
Operating income		$	2.41			$	2.66			$	8.56			$	10.86
Diluted per share data
Net income		$	2.13			$	3.05			$	13.32			$	11.67
Add after tax affect of:
Net realized investment (losses) gains			0.10				(0.72	)			(5.36	)			(2.43	)
Net impairment charges recognized in earnings			—				—				—				0.96
Impairment of intangible assets			—				0.13				—				0.13
Foreign exchange loss			0.01				0.03				0.01				0.01
Operating income		$	2.24			$	2.49			$	7.97			$	10.34

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED DILUTED BOOK VALUE PER SHARE RECONCILIATION
(Expressed in thousands of United States dollars, except share and per share amounts)

		As of				As of
		December 31,				December 31,
		2010				2009
Price per share at period end		$	59.44			$	46.07
Total shareholders’ equity			3,075,820				3,213,295
Basic common shares outstanding			38,089,226				49,734,487
Add: unvested restricted share units			571,178				915,432
Add: Performance based equity awards			1,440,017				1,583,237
Add: employee purchase plan			10,576				—
Add: dilutive options/warrants outstanding			3,272,739				6,805,157
Weighted average exercise price per share		$	35.98			$	34.44
Deduct: options bought back via treasury method			(1,980,884	)			(5,087,405	)
Common shares and common share equivalents outstanding			41,402,852				53,950,908
Basic book value per common share		$	80.75			$	64.61
Diluted book value per common share		$	74.29			$	59.56

ALLIED WORLD ASSURANCE COMPANY HOLDINGS, AG
UNAUDITED ANNUALIZED RETURN ON SHAREHOLDERS’ EQUITY RECONCILIATION
(Expressed in thousands of United States dollars, except for percentage information)

		Quarter Ended December 31,								Year Ended December 31,
		2010				2009				2010				2009
Opening shareholders’ equity		$	3,341,314			$	3,078,894			$	3,213,295			$	2,416,862
Deduct: accumulated other comprehensive income			(111,760	)			(185,043	)			(149,849	)			(105,632	)
Adjusted opening shareholders’ equity			3,229,554				2,893,851				3,063,446				2,311,230
Closing shareholders’ equity		$	3,075,820			$	3,213,295			$	3,075,820			$	3,213,295
Deduct: accumulated other comprehensive income			(57,135	)			(149,849	)			(57,135	)			(149,849	)
Adjusted closing shareholders’ equity			3,018,685				3,063,446				3,018,685				3,063,446
Average shareholders’ equity		$	3,124,120			$	2,978,649			$	3,041,066			$	2,687,338
Net income available to shareholders		$	92,786			$	161,255			$	665,005			$	606,887
Annualized net income available to shareholders			371,144				645,020				665,005				606,887
Annualized return on average shareholders’ equity — net income available to shareholders			11.9	%			21.7	%			21.9	%			22.6	%
Operating income available to shareholders		$	97,288			$	131,920			$	397,831			$	537,726
Annualized operating income available to shareholders			389,152				527,680				397,831				537,726
Annualized return on average shareholders’ equity — operating income available to shareholders			12.5	%			17.7	%			13.1	%			20.0	%

SOURCE Allied World Assurance Company Holdings, AG

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