Exhibit 99.1

ALLEGHANY CORPORATION

7 Times Square Tower, 17^th Floor

New York, NY 10036

ALLEGHANY CORPORATION REPORTS 2013 THIRD QUARTER RESULTS

NEW YORK, NY, November 4, 2013 – Alleghany Corporation (NYSE-Y) today announced its financial results for the three and nine months ended September 30, 2013. Book value per common share¹ grew to $400.60 as of September 30, 2013, an increase of 5.7% from book value per common share of $379.13 at 2012 year-end. Total stockholders’ equity² increased to $6.7 billion as of September 30, 2013 from approximately $6.4 billion as of December 31, 2012.

Alleghany reported net earnings³ of $113.2 million, or $6.75 per diluted share for the 2013 third quarter, compared with $125.4 million, or $7.41 per diluted share for the 2012 third quarter. For the first nine months of 2013, Alleghany reported net earnings³ of $423.2 million, or $25.20 per diluted share, compared with $794.9 million, or $53.14 per diluted share for the first nine months of 2012. Net earnings for the first nine months of 2012 include 208 days of results of TransRe, as well as merger-related items associated with the TransRe merger, including a gain of $494.9 million resulting from the application of purchase accounting treatment, amortization of intangible assets of $213.4 million and transaction costs of $33.8 million.

Beginning this quarter and concurrent with the issuance of today’s earnings press release, Alleghany has posted a financial supplement to its website, www.alleghany.com, containing a number of schedules that provide additional detail pertaining to our financial results.

A summary of Alleghany’s pre-tax results for the three and nine months ended September 30, 2013 and 2012 follows:

Weston M. Hicks, President and chief executive officer, commented, “Alleghany has generated solid year-to-date performance, growing book value per share by 5.7%. This result was driven by our strong year to date underwriting performance, highlighted by an 89.9% combined ratio, and the total return on our investment portfolio, which increased by 1.7% over the same period due largely to strong equity returns.”

“Looking more closely at the third quarter, our results included strong investment returns and mixed underwriting performance. We reported book value growth of 3.4%, with a total investment return of 1.5% in the quarter, as net investment income rose 27.4% to $115.3 million and net unrealized gains on investments increased by $148.4 million due to strong equity returns.”

“Our underwriting results for the quarter reflect flat gross premiums written compared with the prior-year period. TransRe’s net premiums written decreased by 6.3% to $790.1 million from the 2012 third quarter as the company remains disciplined amid a reinsurance market defined by increasing competition and an overall decrease in the amount of risk premium being ceded by large insurers. The insurance segment’s gross premiums written for the 2013 third quarter grew by 15.4% to $341.5 million from the 2012 third quarter, primarily due to new business written at RSUI and price increases at all three of our insurance subsidiaries.”

“The combined ratio for the 2013 third quarter was 94.1%. TransRe’s combined ratio of 92.9% reflects approximately $47 million in catastrophe losses incurred in the quarter, primarily due to severe weather in Mexico, Canada and Germany, which were more than offset by favorable property reserve adjustments of $53.1 million, primarily attributable to Super Storm Sandy. Our insurance operations recorded a combined ratio of 97.7% for the third quarter, driven by RSUI, which incurred catastrophe losses of $22.4 million during the period, primarily from the Colorado floods. Additionally, RSUI recorded a net increase in prior year reserves of $8.9 million largely due to a claim settlement from Hurricane Katrina, following a series of adverse court rulings.”

Mr. Hicks continued, “Our investment strategy remains focused on balancing interest rate risk through the combination of an intermediate duration fixed income portfolio — a prudent position relative to our loss reserves — with equity security exposures that have performed well as interest rates have risen since the beginning of the year. We believe that our previously-announced strategic relationship with Ares Management will provide a reduction to interest rate risk through an allocation to credit strategies with floating interest rates. Simultaneously, we have taken steps to provide some protection against a slip back into a recessionary economy and allocated a portion of our assets to long-dated zero coupon Treasury securities.”

In the first nine months of 2013, Alleghany repurchased an aggregate of 113,160 shares of its common stock in the open market for $40.4 million at an average price per share of $356.92. No shares were repurchased in the third quarter of 2013. Following this activity, Alleghany had $241.9 million remaining on its currently effective $300 million share repurchase authorization.

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2013 Third Quarter Underwriting Results

Alleghany’s underwriting profit for the third quarter of 2013 was $61.8 million, compared with a $166.0 million underwriting profit for the third quarter of 2012. The underwriting results for the 2013 third quarter reflect a $56.0 million underwriting profit for the reinsurance segment (TransRe), compared with a $137.5 million underwriting profit for the 2012 third quarter, as well as an underwriting profit of $5.8 million for the insurance segment, compared with a $28.5 million underwriting profit for the 2012 third quarter.

The decrease in TransRe’s underwriting profit in the third quarter of 2013 from the third quarter of 2012 primarily reflects the absence of merger-related accounting items in the 2013 third quarter, which were significant in the 2012 third quarter. In particular, the significant increase in commissions, brokerage and other underwriting expenses reflects the absence in the 2013 third quarter of the beneficial impact of the acquisition method of accounting on such expenses in the 2012 third quarter. The decrease in underwriting profit for the insurance segment in the third quarter of 2013 from the third quarter of 2012 primarily reflects higher catastrophe losses at RSUI.

Alleghany’s combined ratio for the 2013 third quarter was 94.1%, compared with 84.8% in the 2012 third quarter. TransRe’s combined ratio for the 2013 third quarter was 92.9%, compared with 84.4% for the 2012 third quarter, and the insurance segment’s combined ratio for the 2013 third quarter was 97.7%, compared with 86.5% for the 2012 third quarter. As described above, TransRe’s combined ratio in the third quarter of 2012 was favorably impacted as a result of applying the acquisition method of accounting for the merger. Excluding the impact of the application of the acquisition method of accounting, TransRe’s estimated combined ratio was approximately 93% for the third quarter of 2012.

First Nine Months of 2013 Underwriting Results

Alleghany’s underwriting profit for the first nine months of 2013 was $322.0 million, compared with a $442.3 million underwriting profit for the first nine months of 2012. The underwriting results reflect a $247.9 million underwriting profit for the reinsurance segment (TransRe), compared with a $369.2 million underwriting profit for the first nine months of 2012 in the 208-day period of Alleghany’s ownership of TransRe, and a $74.1 million underwriting profit for the insurance segment, compared with a $73.1 million underwriting profit for the first nine months of 2012.

The decrease in TransRe’s underwriting profit in the first nine months of 2013 from the first nine months of 2012 primarily reflects an increase in commissions, brokerage and other underwriting expenses relative to net premiums earned. As explained above, the results for the first nine months of 2013 reflect the absence of favorable impact arising from the acquisition method of accounting, which was significant in the first nine months of 2012.

The slight increase in insurance segment underwriting profit in the first nine months of 2013 from the first nine months of 2012 primarily reflects the positive impact of growing premiums on all three of Alleghany’s insurance businesses and lower net adverse prior year reserve development at CATA, largely offset by higher catastrophe losses at RSUI and adverse prior year development at PCC.

Total net premiums written for the first nine months of 2013 were $3,285.9 million, compared with $2,700.4 million for the first nine months of 2012. TransRe’s net premiums written for the first nine months of 2013 increased by 23.6% to $2,499.4 million from the first nine months of 2012, reflecting the fact that the first nine months of 2012 did not include net premiums written by TransRe prior to the March 6, 2012 merger date. The insurance segment’s net premiums written for the first nine months of 2013 increased by 16.0% to $786.5 million from the first nine months of 2012, primarily due to new business written and modest casualty price increases.

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Alleghany’s combined ratio for the first nine months of 2013 was 89.9%, compared with 83.1% in the first nine months of 2012. TransRe’s combined ratio for the first nine months of 2013 was 90.0%, compared with 81.7% for the first nine months of 2012, and the insurance segment’s combined ratio for the first nine months of 2013 was 89.4%, compared with 87.9% for the first nine months of 2012. As noted above, TransRe’s combined ratio was favorably impacted as a result of applying the acquisition method of accounting for the merger because deferred acquisition costs were written off at the March 6, 2012 merger date. As of March 6, 2013, the application of the acquisition method of accounting no longer had a significant impact on TransRe’s combined ratio. Excluding the impact of the application of the acquisition method of accounting, TransRe’s estimated combined ratio was approximately 92% for the first nine months of 2012.

Investment Performance

Alleghany’s net investment income for the three and nine months ended September 30, 2013 was $115.3 million and $334.5 million, respectively, an increase of 27.4% and 42.6% over the corresponding 2012 periods. The 42.6% increase in the first nine months of 2013 primarily reflects the fact that the first nine months of 2012 did not include net investment income of TransRe prior to the March 6, 2012 merger date. The interest income earned on TransRe’s fixed income portfolio is net of a significant increase to amortization expense resulting from the write-up of the portfolio’s amortized cost basis to its fair value as of the date of the merger. This increased amortization expense reduced TransRe’s reported net investment income, compared with TransRe’s net investment income prior to the merger.

Additional Information

Additional information regarding Alleghany’s 2013 third quarter and year-to-date financial results, including management’s discussion and analysis of Alleghany’s financial condition and results of operations, is contained in Alleghany’s Quarterly Report on Form 10-Q for the period ended September 30, 2013 (the “Form 10-Q”), to be filed with the U.S. Securities and Exchange Commission (the “SEC”) on or about the date hereof. In addition, comparative supplemental financial information is available in the 2013 third quarter financial supplement (the “Financial Supplement”). The Form 10-Q and the Financial Supplement will be available on Alleghany’s website at www.alleghany.com and on the SEC’s website at www.sec.gov. Readers are urged to review the Form 10-Q for a more complete discussion of Alleghany’s financial performance.

About Alleghany Corporation

Alleghany Corporation (NYSE-Y) creates value through owning and managing operating subsidiaries and investments, anchored by a core position in property and casualty reinsurance and insurance. Alleghany’s property and casualty subsidiaries include: Transatlantic Holdings, Inc. (referred to herein as “TransRe”), a leading global reinsurer; RSUI Group, Inc. (referred to herein as “RSUI”), a national underwriter of property and liability specialty insurance coverages; Capitol Transamerica Corporation (referred to herein as “CATA”), an underwriter of small commercial property, casualty and surety insurance coverages; and Pacific Compensation Corporation (referred to herein as “PCC”), an underwriter of workers’ compensation insurance primarily in California.

Non-GAAP Financial Measures

Throughout this press release, Alleghany’s results of operations have been presented in the way that Alleghany believes will be the most meaningful and useful to investors, analysts, rating agencies and others who use financial information in evaluating the performance of Alleghany. This presentation includes the use of underwriting profit and net earnings before merger-related items and income taxes, which are “non-GAAP financial measures,” as such term is defined in Regulation G promulgated by the SEC.

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Underwriting profit represents net premiums earned less net loss and loss adjustment expense and commissions, brokerage and other underwriting expenses, all as determined in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”), and does not include net investment income, net realized capital gains, other than temporary impairment losses, other income, other operating expenses, amortization of intangible assets or interest expense. Alleghany consistently uses underwriting profit as a supplement to earnings before income taxes, the most comparable U.S. GAAP financial measure, to evaluate the performance of its segments and believes that underwriting profit provides useful additional information to investors because it highlights net earnings attributable to a segment’s underwriting performance. Earnings before income taxes may show a profit despite an underlying underwriting loss, and when underwriting losses persist over extended periods, a reinsurance or an insurance company’s ability to continue as an ongoing concern may be at risk.

Net earnings before merger-related items and income taxes represents earnings before income taxes, excluding gain on bargain purchase, amortization of intangible assets and merger-related transaction costs, all as determined in accordance with U.S. GAAP. Alleghany uses net earnings before merger-related items and income taxes as a supplement to earnings before income taxes, the most comparable U.S. GAAP financial measure, to provide useful additional information to investors by highlighting earnings before income taxes attributable to its performance exclusive of non-recurring merger-related impacts.

These non-GAAP financial measures are not meant to be considered in isolation or as a substitute for measures of operating performance prepared in accordance with U.S. GAAP. Reconciliation of underwriting profit to earnings before income taxes and net earnings before merger-related items and income taxes to earnings before income taxes is presented herein.

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Forward-looking Statements

This release contains disclosures which are forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements that do not relate solely to historical or current facts, and can be identified by the use of words such as “may,” “will,” “expect,” “project,” “estimate,” “anticipate,” “plan,” “believe,” “potential,” “should,” “continue” or the negative versions of those words or other comparable words. These forward-looking statements are based upon Alleghany’s current plans or expectations and are subject to a number of uncertainties and risks that could significantly affect current plans, anticipated actions and Alleghany’s future financial condition and results. These statements are not guarantees of future performance, and Alleghany has no specific intention to update these statements. The uncertainties and risks include, but are not limited to,

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Additional risks and uncertainties include general economic and political conditions, including the effects of a prolonged U.S. or global economic downturn or recession; changes in costs; variations in political, economic or other factors; risks relating to conducting operations in a competitive environment; effects of acquisition and disposition activities, inflation rates, or recessionary or expansive trends; changes in interest rates; extended labor disruptions, civil unrest, or other external factors over which Alleghany has no control; and changes in Alleghany’s plans, strategies, objectives, expectations, or intentions, which may happen at any time at its discretion. As a consequence, current plans, anticipated actions, and future financial condition and results may differ from those expressed in any forward-looking statements made by Alleghany or on its behalf.

For more information, please contact:

Jeff Majtyka/Mike Smargiassi

Brainerd Communicators, Inc.

212-986-6667

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ALLEGHANY CORPORATION AND SUBSIDIARIES

Consolidated Balance Sheets

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ALLEGHANY CORPORATION AND SUBSIDIARIES

Consolidated Statements of Earnings and Comprehensive Income

(unaudited)

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ALLEGHANY CORPORATION AND SUBSIDIARIES

Consolidated Statements of Earnings and Comprehensive Income

(unaudited)

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