Exhibit 99.1

HCC INSURANCE HOLDINGS REPORTS EARNINGS
FOR THE THIRD QUARTER AND
FIRST NINE MONTHS OF 2010 AND
INTRODUCES REPORTING SEGMENT CHANGES

HOUSTON (November 2, 2010) . . .
HCC Insurance Holdings, Inc. (NYSE: HCC) today released results for its third quarter ended
September 30, 2010.

Net earnings for the third quarter of 2010 were $93.1 million, compared with $94.3 million during the third quarter of 2009. Net earnings per diluted share were $0.81 for the third quarter of 2010, compared to $0.83 for the same quarter of 2009. Net earnings for the first nine months of 2010 were $247.8 million, or $2.15 per diluted share, versus $269.1 million, or $2.37 per diluted share, for the first nine months of the previous year.

During the third quarter of 2010, the Company repurchased 407,166 shares of common stock at an average price of $25.10 per share. For the first nine months of 2010, the Company repurchased 457,316 shares of common stock at an average price of $25.02 per share. The Company has $289.0 million remaining under its $300 million share buyback authorization.

The GAAP combined ratio for the third quarter of 2010 was 82.1%, compared to 81.3% for the same quarter of 2009, and 85.3% in the first nine months of 2010, compared to 83.4% in the corresponding period of 2009.

The accident year combined ratio was 82.2% for the third quarter of 2010 and 85.1% for the first nine months of 2010, compared to 86.2% and 85.8% for the same periods in 2009, respectively. The accident year combined ratio for the first nine months of 2010 includes 1.0 percentage point for catastrophes. Book value per share increased to $28.95 at September 30, 2010, compared to $26.58 at December 31, 2009. The Company’s annualized return on average equity for the third quarter of 2010 was 11.4%.

For the third quarter of 2010, the gross written premium of HCC’s insurance company subsidiaries increased 3% to $640.7 million, compared to $620.4 million for the same quarter of 2009. Net written premium increased to $494.4 million in 2010, compared with net written premium of $493.3 million in 2009. Net earned premium decreased to $516.2 million for the third quarter of 2010, compared to $520.1 million for the same quarter of 2009. During the first nine months of 2010, gross written premium increased 3% to $2.0 billion, and net written premium and net earned premium increased slightly to

$1.5 billion, compared to the first nine months of 2009.

“We continue to be pleased with our 2010 performance. The third quarter was another solid quarter in a continuing difficult environment. Our premium volume and loss and expense ratios are a reflection of our strategy of building a diverse portfolio of specialty businesses,” said John N. Molbeck, Jr., HCC President and Chief Executive Officer.

During the third quarter of 2010, HCC had net favorable prior year reserve development of $0.9 million, compared to $25.4 million for the same period in 2009. For the first nine months of 2010, the Company recorded $1.3 million of net adverse prior year reserve development, compared to net favorable prior year reserve development of $36.6 million for the same period in 2009.

Investment income increased during the third quarter of 2010 to $51.1 million, compared to $48.1 million a year earlier, reflecting an increased amount of invested assets. On a year-to-date basis, investment income increased to $150.6 million in 2010 from $141.7 million in 2009. The Company’s fixed income investments increased 10% from September 30, 2009 to $5.4 billion at September 30, 2010. As of September 30, 2010, HCC’s fixed income securities portfolio had an average rating of AA+, an average duration of 4.6 years and an average tax equivalent yield of 4.9%.

The Company’s liquidity position remains strong and its shareholders’ equity was $3.3 billion at September 30, 2010. The Company held $572.3 million of cash and short-term investments at the end of the quarter. HCC has a $575.0 million revolving loan facility with $556.6 million of available capacity at September 30, 2010. The Company generated $175.3 million and $314.6 million of cash flow from operating activities in the third quarter and first nine months of 2010, respectively, compared to $155.4 million and $417.5 million for the same periods in 2009.

As of September 30, 2010, total investments were $5.8 billion, total assets were $9.3 billion, and the Company’s debt to total capital ratio was 8.2%.

The Company also announced its new reporting segment structure, which was completed during the third quarter of 2010. The new segments are the result of the reorganization of the Company’s management structure around its key lines of business. Beginning this quarter, the Company will report results in these six segments, each of which reports to an executive responsible for that segment’s results:

• U.S. Property & Casualty

• Professional Liability

• Accident & Health

• U.S. Surety & Credit

• International

• Investing

The first five segments report the results of HCC’s insurance underwriting businesses,

2

including its underwriting agencies that produce the business. Segment results will be measured based on pretax underwriting profit. The consolidated investment portfolio, its related net investment income and any net realized investment gains and losses will be included in the Investing segment. Previously, HCC reported its results in the Insurance Company, Agency, and Other Operations segments. Prior period information has been adjusted to reflect the new reporting segment structure.

Included in the portfolio of products for each insurance segment are the following key products:

• U.S. Property & Casualty — aviation, small account errors and omissions liability, public risk, employment practices liability, title, residual value, disability, kidnap and ransom, contingency and brown water marine written in the United States.

• Professional Liability — directors’ and officers’ liability, large account errors and omissions liability, diversified financial products and fidelity written in the United States and internationally.

• Accident & Health — medical stop-loss, short-term domestic and international medical, HMO reinsurance and medical excess written in the United States.

• U.S. Surety & Credit — contract, commercial, court and bail bonds written in the United States and credit insurance managed in the United States.

• International — energy, property treaty, liability, surety, credit, property, ocean marine, accident and health and other smaller product lines written outside the United States.

The Company’s remaining operations will be reported in a Corporate & Other category, which includes corporate operating expenses not allocable to the segments, interest expense on long-term debt, and underwriting results of our Exited Lines. The Exited Lines are six lines of business that HCC no longer writes and does not expect to write in the future, and include: 1) accident and health business managed by our underwriting agency, LDG Reinsurance, 2) workers’ compensation, 3) provider excess, 4) Spanish medical malpractice, 5) U.K. motor and 6) film completion bonds.

In connection with the new segments, HCC changed the presentation of its consolidated income statement to better represent its current operations. Previously, HCC presented reinsurance ceding commissions that exceeded policy acquisition costs as a component of fee and commission income, within total revenue. HCC now presents all ceding commissions as an offset to policy acquisition costs, within total expense. Any remaining fee and commission income is now classified as a component of other operating income, within total revenue.

Finally, HCC has also changed the definition of its consolidated expense ratio for all periods presented. The expense ratio is calculated as the sum of other expense

3

(excluding loss and loss adjustment expense) for each of the insurance segments, divided by the sum of total revenue for each of the insurance segments. The expense ratio excludes investment income and activity included in Corporate & Other.

For further information about HCC’s results, the supplemental financial schedules are accessible on the Company’s website at http://www.hcc.com, as well as directly in the Investor Relations section of HCC’s website at http://ir.hcc.com.

(Note: If clicking on the above links does not open in a new web page, please cut and paste the above URLs into your browser’s address bar.)

HCC will hold an open conference call beginning at 8:00 a.m. Central Daylight Time on Wednesday, November 3, 2010. To participate, the number for domestic calls is (800) 374-0290 and the number for international calls is (706) 634-0161. In addition, there will be a live webcast available on a listen-only basis that can be accessed through the HCC website at www.hcc.com. The webcast replay will be archived in the Investor Relations section of the HCC website through Friday, February 25, 2011.

Headquartered in Houston, Texas, HCC Insurance Holdings, Inc. is a leading international specialty insurance group with offices across the United States and in the United Kingdom, Spain and Ireland. As of September 30, 2010, HCC had assets of $9.3 billion and shareholders’ equity of $3.3 billion. HCC’s major domestic and international insurance companies have a financial strength rating of “AA (Very Strong)” from Standard & Poor’s Corporation. HCC’s major domestic insurance companies have a financial strength rating of “AA (Very Strong)” from Fitch Ratings, “A1 (Good Security)” from Moody’s Investors Service, Inc., and “A+ (Superior)” by A.M. Best Company, Inc.

For more information, visit our website at www.hcc.com.

Contact:	Jonathan Lee, HCC Director of Investor Relations
	Telephone: (713) 996-1156

Forward-looking statements contained in this press release are made under “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 and involve a number of risks and uncertainties. The types of risks and uncertainties which may affect the Company are set forth in its periodic reports filed with the Securities and Exchange Commission.

* * * *

4

HCC Insurance Holdings, Inc. and Subsidiaries
Financial Highlights

(Unaudited, in thousands except per share data)

	Nine months ended						Three months ended
	September 30,						September 30,
	2010			2009			2010			2009
Gross written premium	$	1,954,730		$	1,904,086		$	640,656		$	620,382
Net written premium		1,539,491			1,527,889			494,438			493,287
Net earned premium		1,532,138			1,524,425			516,166			520,059
Net investment income		150,603			141,740			51,137			48,111
Other operating income (a)		35,035			69,765			7,888			12,166
Total revenue (a)		1,725,373			1,735,503			575,948			580,875
Net earnings		247,797			269,076			93,063			94,321
Earnings per share (diluted)	$	2.15		$	2.37		$	0.81		$	0.83
Weighted-average shares outstanding (millions)		114.1			112.9			114.2			112.9
GAAP net loss ratio		60.2	%		59.8	%		57.6	%		58.4	%
GAAP combined ratio (a)		85.3	%		83.4	%		82.1	%		81.3	%
Paid loss ratio		57.0	%		55.0	%		58.0	%		60.2	%

	September 30,			December 31,
	2010			2009
Total investments	$	5,835,049		$	5,456,229
Total assets		9,293,895			8,834,391
Shareholders’ equity		3,337,102			3,031,183
Debt to total capital ratio		8.2	%		9.0	%
Book value per share	$	28.95		$	26.58

(a) 2009 amounts changed to be consistent with 2010 presentation.

S - 1

HCC Insurance Holdings, Inc. and Subsidiaries
Consolidated Balance Sheets

(Unaudited, in thousands)

	September 30,			December 31,
	2010			2009
ASSETS
Investments:
Fixed income securities — available for sale, at fair value	$	5,166,709		$	4,538,073
Fixed income securities — held to maturity, at amortized cost		193,841			102,792
Short-term investments		474,066			810,673
Other investments		433			4,691
Total investments		5,835,049			5,456,229
Cash		98,213			129,460
Restricted cash and cash investments		157,677			146,133
Premium, claims and other receivables		658,670			600,332
Reinsurance recoverables		1,042,650			1,016,411
Ceded unearned premium		283,529			270,436
Ceded life and annuity benefits		58,985			61,313
Deferred policy acquisition costs		219,062			208,463
Goodwill		821,700			822,006
Other assets		118,360			123,608
Total assets	$	9,293,895		$	8,834,391
LIABILITIES
Loss and loss adjustment expense payable	$	3,555,505		$	3,492,309
Life and annuity policy benefits		58,985			61,313
Reinsurance balances payable		202,202			182,661
Unearned premium		1,069,594			1,044,747
Deferred ceding commissions		72,714			71,595
Premium and claims payable		142,445			154,596
Notes payable		298,598			298,483
Accounts payable and accrued liabilities		556,750			497,504
Total liabilities		5,956,793			5,803,208
SHAREHOLDERS’ EQUITY
Common stock		120,398			118,724
Additional paid-in capital		940,745			914,339
Retained earnings		2,177,266			1,977,254
Accumulated other comprehensive income		208,936			119,665
Treasury stock		(110,243	)		(98,799	)
Total shareholders’ equity		3,337,102			3,031,183
Total liabilities and shareholders’ equity	$	9,293,895		$	8,834,391

S - 2

HCC Insurance Holdings, Inc. and Subsidiaries
Consolidated Statements of Earnings

(Unaudited, in thousands except per share data)

	Nine months ended						Three months ended
	September 30,						September 30,
	2010			2009			2010			2009
REVENUE
Net earned premium	$	1,532,138		$	1,524,425		$	516,166		$	520,059
Net investment income		150,603			141,740			51,137			48,111
Other operating income (a)		35,035			69,765			7,888			12,166
Net realized investment gain		7,897			4,852			1,057			864
Other-than-temporary impairment loss
Total loss		(316	)		(6,089	)		(316	)		(380	)
Portion recognized in equity, before tax		16			810			16			55
Net loss recognized in earnings		(300	)		(5,279	)		(300	)		(325	)
Total revenue (a)		1,725,373			1,735,503			575,948			580,875
EXPENSE
Loss and loss adjustment expense, net		922,645			911,944			297,138			303,808
Policy acquisition costs, net (a)		242,078			223,186			80,748			71,492
Other operating expense		189,953			195,509			60,770			64,985
Interest expense		15,907			11,816			5,280			3,549
Total expense		1,370,583			1,342,455			443,936			443,834
Earnings before income tax expense		354,790			393,048			132,012			137,041
Income tax expense		106,993			123,972			38,949			42,720
Net earnings	$	247,797		$	269,076		$	93,063		$	94,321
Basic earnings per share data:
Net earnings per share	$	2.15		$	2.39		$	0.81		$	0.84
Weighted-average shares outstanding (millions)		113.9			112.2			114.0			111.9
Diluted earnings per share data:
Net earnings per share	$	2.15		$	2.37		$	0.81		$	0.83
Weighted-average shares outstanding (millions)		114.1			112.9			114.2			112.9
Cash dividends declared, per share	$	0.415		$	0.385		$	0.145		$	0.135

(a) 2009 amounts changed to be consistent with 2010 presentation.

S - 3

HCC Insurance Holdings, Inc. and Subsidiaries
Consolidated Statements of Cash Flows

(Unaudited, in thousands)

	Nine months ended
	September 30,
	2010			2009
Operating activities
Net earnings	$	247,797		$	269,076
Adjustments to reconcile net earnings to net cash provided by operating activities:
Change in premium, claims and other receivables		(36,040	)		36,443
Change in reinsurance recoverables		(32,474	)		14,853
Change in ceded unearned premium		(15,368	)		(25,093	)
Change in loss and loss adjustment expense payable		76,829			51,519
Change in reinsurance balances payable		21,435			24,548
Change in unearned premium		30,471			39,441
Change in premium and claims payable, net of restricted cash		(9,934	)		(63,727	)
Change in accounts payable and accrued liabilities		12,593			22,132
Stock-based compensation expense		9,441			12,472
Depreciation and amortization expense		12,894			11,796
Gain on investments		(8,086	)		(3,152	)
Other, net		5,073			27,238
Cash provided by operating activities		314,631			417,546
Investing activities
Sales of available for sale fixed income securities		132,897			337,615
Maturity or call of available for sale fixed income securities		458,495			260,839
Maturity or call of held to maturity fixed income securities		25,187			86,190
Cost of available for sale fixed income securities acquired		(1,048,010	)		(1,020,506	)
Cost of held to maturity fixed income securities acquired		(115,215	)		(59,677	)
Change in short-term investments		328,951			(91,617	)
Proceeds from sales of strategic and other investments		4,577			114,940
Payments for purchase of businesses, net of cash received		(36,348	)		(37,995	)
Proceeds from sale of subsidiaries		15,278			6,188
Other, net		(6,755	)		(13,109	)
Cash used by investing activities		(240,943	)		(417,132	)
Financing activities
Advances on line of credit		—			115,000
Payments on line of credit		—			(15,032	)
Payments on convertible notes		(64,472	)		—
Sale of common stock		18,639			9,423
Purchase of common stock		(11,444	)		(35,464	)
Dividends paid		(46,532	)		(42,244	)
Other, net		(1,126	)		(2,570	)
Cash provided (used) by financing activities		(104,935	)		29,113
Net increase (decrease) in cash		(31,247	)		29,527
Cash at beginning of year		129,460			27,347
Cash at end of period	$	98,213		$	56,874

S - 4

HCC Insurance Holdings, Inc. and Subsidiaries
Gross Written Premium

(Unaudited, in thousands)

	Nine months ended September 30,							Three months ended September 30,
	2010		2009		Change			2010		2009		Change
U.S. Property & Casualty
Aviation	$	121,600	$	133,913		(9	)%	$	44,692	$	50,162		(11	)%
E&O		63,316		84,118		(25	)		19,018		26,760		(29	)
Public Risk		50,397		52,071		(3	)		15,706		16,194		(3	)
Other		179,826		205,243		(12	)		66,594		66,382		—
		415,139		475,345		(13	)		146,010		159,498		(8	)
Professional Liability
U.S. D&O		267,302		289,226		(8	)		98,813		103,324		(4	)
International D&O		69,926		67,612		3			20,554		23,409		(12	)
Other		77,208		78,983		(2	)		25,553		24,709		3
		414,436		435,821		(5	)		144,920		151,442		(4	)
Accident & Health
Medical Stop-loss		488,256		473,273		3			164,698		157,429		5
Other		79,529		77,652		2			29,679		27,994		6
		567,785		550,925		3			194,377		185,423		5
U.S. Surety & Credit
Surety		132,137		114,668		15			43,437		41,916		4
Credit		41,005		33,776		21			12,535		10,189		23
		173,142		148,444		17			55,972		52,105		7
International
Energy		97,053		92,277		5			16,731		14,645		14
Property Treaty		71,404		—	nm				16,309		—	nm
Liability		68,501		66,466		3			19,464		20,795		(6	)
Surety & Credit		57,019		55,149		3			16,774		15,574		8
Other		87,998		56,032		57			29,919		13,878		116
		381,975		269,924		42			99,197		64,892		53
Exited Lines		2,253		23,627	nm				180		7,022	nm
Totals	$	1,954,730	$	1,904,086		3	%	$	640,656	$	620,382		3	%

nm — Not meaningful comparison

S - 5

HCC Insurance Holdings, Inc. and Subsidiaries
Net Written Premium

(Unaudited, in thousands)

	Nine months ended September 30,							Three months ended September 30,
	2010		2009		Change			2010		2009		Change
U.S. Property & Casualty
Aviation	$	84,097	$	95,655		(12	)%	$	30,347	$	34,779		(13	)%
E&O		63,256		84,055		(25	)		19,019		26,759		(29	)
Public Risk		36,635		39,647		(8	)		12,985		11,796		10
Other		63,729		80,578		(21	)		21,899		23,887		(8	)
		247,717		299,935		(17	)		84,250		97,221		(13	)
Professional Liability
U.S. D&O		198,043		219,377		(10	)		73,037		79,541		(8	)
International D&O		28,074		37,187		(25	)		8,260		12,486		(34	)
Other		51,839		53,399		(3	)		17,834		15,700		14
		277,956		309,963		(10	)		99,131		107,727		(8	)
Accident & Health
Medical Stop-loss		488,256		473,271		3			164,698		157,429		5
Other		79,264		77,292		3			29,603		27,855		6
		567,520		550,563		3			194,301		185,284		5
U.S. Surety & Credit
Surety		127,348		110,502		15			42,038		40,026		5
Credit		32,278		29,213		10			10,029		7,895		27
		159,626		139,715		14			52,067		47,921		9
International
Energy		51,716		50,268		3			4,251		2,551		67
Property Treaty		61,994		—	nm				12,948		—	nm
Liability		63,410		59,641		6			17,663		19,603		(10	)
Surety & Credit		51,278		49,953		3			14,605		14,818		(1	)
Other		57,365		45,188		27			15,177		11,304		34
		285,763		205,050		39			64,644		48,276		34
Exited Lines		909		22,663	nm				45		6,858	nm
Totals	$	1,539,491	$	1,527,889		1	%	$	494,438	$	493,287		—	%

nm — Not meaningful comparison

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HCC Insurance Holdings, Inc. and Subsidiaries
Net Earned Premium

(Unaudited, in thousands)

	Nine months ended September 30,							Three months ended September 30,
	2010		2009		Change			2010		2009		Change
U.S. Property & Casualty
Aviation	$	87,248	$	98,514		(11	)%	$	28,950	$	33,053		(12	)%
E&O		74,079		90,468		(18	)		23,013		29,604		(22	)
Public Risk		34,526		28,853		20			11,600		11,045		5
Other		62,574		71,360		(12	)		21,239		20,751		2
		258,427		289,195		(11	)		84,802		94,453		(10	)
Professional Liability
U.S. D&O		229,034		225,412		2			73,835		81,737		(10	)
International D&O		36,749		44,799		(18	)		10,975		19,009		(42	)
Other		56,066		60,403		(7	)		18,886		20,641		(9	)
		321,849		330,614		(3	)		103,696		121,387		(15	)
Accident & Health
Medical Stop-loss		488,256		473,271		3			164,698		157,429		5
Other		79,483		80,696		(2	)		28,554		28,508	nm
		567,739		553,967		2			193,252		185,937		4
U.S. Surety & Credit
Surety		119,325		107,995		10			39,777		37,598		6
Credit		29,102		27,441		6			10,030		8,111		24
		148,427		135,436		10			49,807		45,709		9
International
Energy		39,566		34,968		13			12,777		12,546		2
Property Treaty		32,533		—	nm				16,924		—	nm
Liability		60,478		61,363		(1	)		19,929		20,687		(4	)
Surety & Credit		53,800		50,429		7			17,916		17,778		1
Other		48,094		42,388		13			16,993		14,410		18
		234,471		189,148		24			84,539		65,421		29
Exited Lines		1,225		26,065	nm				70		7,152	nm
Totals	$	1,532,138	$	1,524,425		1	%	$	516,166	$	520,059		(1	)%

nm — Not meaningful comparison

S - 7

HCC Insurance Holdings, Inc. and Subsidiaries
Net Investment Income and Unrealized Gain

(Unaudited, in thousands)

	Nine months ended						Three months ended
	September 30,						September 30,
	2010			2009			2010			2009
Sources of net investment income:
Fixed income securities
Taxable	$	82,416		$	78,894		$	27,613		$	26,795
Exempt from U.S. income taxes		67,585			61,589			23,308			20,776
Total fixed income securities		150,001			140,483			50,921			47,571
Short-term investments		631			1,791			271			321
Other		3,053			2,194			1,011			1,143
Total investment income		153,685			144,468			52,203			49,035
Investment expense		(3,082	)		(2,728	)		(1,066	)		(924	)
Net investment income	$	150,603		$	141,740		$	51,137		$	48,111
Unrealized gain on available for sale fixed income securities:
Increase in unrealized gain for period, before tax	$	144,953		$	193,870		$	76,321		$	135,831
Unrealized gain at:
September 30, 2010	$	301,264
June 30, 2010	$	224,943
March 31, 2010	$	163,883
December 31, 2009	$	156,311

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HCC Insurance Holdings, Inc. and Subsidiaries
Net Loss Ratios

(Unaudited, in thousands)

	Nine months ended					Nine months ended					Twelve months ended
	September 30, 2010					September 30, 2009					December 31, 2009
	Net earned		Loss			Net earned		Loss			Net earned		Loss
	premium		ratio			premium		ratio			premium		ratio
U.S. Property & Casualty
Aviation	$	87,248		62.7	%	$	98,514		60.3	%	$	129,626		56.6	%
E&O		74,079		84.9			90,468		63.1			118,834		61.5
Public Risk		34,526		58.8			28,853		64.1			39,986		66.3
Other		62,574		42.8			71,360		41.1			90,993		31.2
		258,427		63.7			289,195		56.8			379,439		53.1
Professional Liability
U.S. D&O		229,034		61.0			225,412		62.8			306,621		62.2
International D&O		36,749		60.5			44,799		49.3			59,082		53.3
Other		56,066		60.9			60,403		64.8			78,831		68.9
		321,849		60.9			330,614		61.3			444,534		62.2
Accident & Health
Medical Stop-loss		488,256		74.0			473,271		73.7			633,572		71.7
Other		79,483		64.4			80,696		71.6			107,967		80.5
		567,739		72.6			553,967		73.4			741,539		72.9
U.S. Surety & Credit
Surety		119,325		22.2			107,995		22.0			147,803		22.8
Credit		29,102		40.3			27,441		58.8			34,824		59.9
		148,427		25.7			135,436		29.4			182,627		29.9
International
Energy		39,566		25.4			34,968		17.9			49,099		25.7
Property Treaty		32,533		47.0			—		—			51	nm
Liability		60,478		55.4			61,363		25.6			82,137		25.7
Surety & Credit		53,800		38.1			50,429		53.0			68,162		50.9
Other		48,094		58.8			42,388		47.8			56,673		46.1
		234,471		45.9			189,148		36.4			256,122		36.9
Exited Lines		1,225	nm				26,065	nm				32,974	nm
Totals	$	1,532,138		60.2	%	$	1,524,425		59.8	%	$	2,037,235		59.7	%

nm — Not meaningful comparison

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