Exhibit 99.1

ALLEGHANY CORPORATION

1411 Broadway, 34^th Floor

New York, NY 10018

ALLEGHANY CORPORATION REPORTS 2018 SECOND QUARTER RESULTS

Book value per common share increases 2.8% in the second quarter

NEW YORK, NY, August 2, 2018 – Alleghany Corporation (NYSE-Y) announced today its financial results for the second quarter and first six months of 2018.

Weston Hicks, President and chief executive officer, stated, “Total revenues grew 22% in the second quarter contributing to strong earnings and solid growth in book value. Book value per common share¹ increased 2.8% in the second quarter and 1.3% year to date to $560.49 as of June 30, 2018. Including the $10 per share special dividend paid on March 15, 2018, book value per common share¹ increased 3.1% year to date. Our second quarter results reflect strong earnings at Alleghany Capital, solid underwriting at TransRe, and strong equity gains, which beginning in 2018 are included in the income statement. In addition, increased investment income and a lower effective tax rate contributed to an approximate 47% improvement in Alleghany’s operating earnings.

Both RSUI and CapSpecialty delivered strong growth in premiums written in the second quarter of 2018, as they capitalized on a number of opportunities across their businesses. These two businesses together produced a 9.6% increase in net premiums written in the second quarter. This growth largely offset the second quarter 2017 premium contribution for PacificComp, which was sold at year-end 2017.”

Mr. Hicks concluded, “Alleghany Capital’s overall performance was strong in the second quarter. Revenue growth was driven by the additions of W&W|AFCO Steel and Wilbert Funeral Services in 2017. Operating earnings before taxes were up 415% to $13.4 million in the second quarter of 2018, compared with the second quarter of 2017. Growth in earnings at Kentucky Trailer, Bourn & Koch and IPS, as well as the additions of W&W|AFCO Steel and Wilbert Funeral Services, were the main contributors to the growth in operating earnings.”

During the second quarter, Alleghany repurchased approximately $214.8 million worth of its shares at an average price of $582.92. At its June 2018 Board meeting, Alleghany’s Board of Directors authorized, upon completion of its previously announced program, the repurchase of additional shares of common stock, at such times and prices as management determines to be advisable, up to an aggregate of $400.0 million.

The following table summarizes the changes in book value per common share¹ for the three and six months ended June 30, 2018:

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The following table summarizes results for the three and six months ended June 30, 2018 and 2017:

SEGMENT RESULTS

The following table summarizes the reinsurance and insurance segment results for the three and six months ended June 30, 2018 and 2017:

Reinsurance

TransRe’s net premiums written in the 2018 second quarter were roughly flat with the comparable prior year second quarter as a result of higher ceded premiums written due to an increase in retrocessional coverage purchased in 2018, largely offset by increases in casualty premiums written by the European and Asia-Pacific operations and the impact of changes in foreign currency exchange rates. Net premiums written for the first six months of 2018 increased over the corresponding 2017 six-month period, largely due to changes in foreign currency exchange rates and an increase in casualty premiums written by TransRe’s European and Asia-Pacific operations. In addition, gross premiums written for a large whole-account quota share treaty (the “Quota Share Treaty”) increased in the second quarter of 2018 from the second quarter of 2017 and decreased in the first six months of 2018 from the first six months of 2017. Premiums related to the Quota Share Treaty were $187.7 million and $183.9 million in the second quarter of 2018 and 2017, respectively, and $371.7 million and $374.1 million in the first six months of 2018 and 2017, respectively. TransRe remains cautious in the current environment and will be patient until it sees sufficient improvement in rates to warrant meaningful growth in premium writings.

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TransRe’s 2018 second quarter combined ratio was 92.8%, compared with 93.5% for the 2017 second quarter, and TransRe’s combined ratio for the first six months of 2018 was 91.4%, compared with 93.9% for the first six months of 2017. TransRe’s lower combined ratio and higher underwriting profit for the second quarter and first six months of 2018 primarily reflect the impact of increases in net premiums earned and, for the first six months of 2018, an increase in favorable prior accident year loss reserve development. TransRe’s combined ratio and underwriting profit for the first six months of 2017 were hurt by $24.4 million of unfavorable prior accident year loss reserve development resulting from the U.K. Ministry of Justice’s significant reduction to the discount rate, referred to as the Ogden rate, used to calculate lump-sum bodily injury payouts in personal injury insurance claims in the U.K.

Insurance

The decrease in net premiums written in the second quarter and first six months of 2018 from the corresponding 2017 periods reflects the sale of PacificComp in the fourth quarter of 2017, partially offset by growth at CapSpecialty and RSUI. Excluding PacificComp from the second quarter and first six months of 2017, net premiums written increased by 9.6% and 7.5% in the second quarter and first six months of 2018, respectively. For the second quarter and first six months of 2018, CapSpecialty’s net premiums written increased by 20.3% and 17.2%, respectively, and RSUI’s net premiums written increased by 6.0% and 4.3%, respectively, over the comparable prior year periods. CapSpecialty’s net premiums written growth is attributable to increased writings in all of its lines of business and the additional premiums written in connection with its recently completed renewal rights transaction for a book of environmental business. The increase at RSUI is due to increased writings across most lines of business and reflects an increase in business opportunities due to improved general market conditions and pricing increases in the property lines of business.

The insurance segment’s combined ratio was 89.5% for the 2018 second quarter, compared with 88.4% for the 2017 second quarter, and the insurance segment’s combined ratio for the first six months of 2018 was 88.3%, compared with 85.8% for the first six months of 2017. The higher combined ratio and lower underwriting profit for the second quarter and first six months of 2018 primarily reflect decreases in favorable prior accident year loss reserve development and higher catastrophe losses incurred at RSUI. The increase in net loss and loss adjustment expenses in the first six months of 2018 over the comparable 2017 period also reflects higher non-catastrophe property losses at RSUI.

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Alleghany Capital

The following table summarizes earnings (losses) before income taxes and operating earnings (losses) before income taxes for the Alleghany Capital segment for the three and six months ended June 30, 2018 and 2017:

Alleghany Capital’s earnings (losses) before income taxes improved to $7.5 million and $6.1 million in the second quarter and first six months of 2018, compared with ($2.2) million and ($3.9) million in the second quarter and first six months of 2017, respectively. The increases in Alleghany Capital’s operating earnings before income taxes in the second quarter and first six months of 2018 reflect increased earnings in the industrial businesses and decreased corporate and other expenses, partially offset by lower earnings in the non-industrial businesses. The increases in the industrial business operating earnings before income taxes in the second quarter and first six months of 2018 reflect the impact from the acquisitions of W&W|AFCO Steel and Hirschfeld Industries group of companies and Alleghany Capital’s investment in Wilbert Funeral Services, as well as solid growth at Kentucky Trailer and Bourn & Koch. The lower non-industrial operating earnings before income taxes in 2018 reflects higher expenses at Jazwares. Jazwares’ earnings in the second quarter were hurt by expenses related to the liquidation of a large toy retailer and expenses incurred in connection with expansion to handle new brands and licenses, such as the recently announced partnership with Epic Games for a wide-ranging toy line based on the extremely popular Fortnite^TM video game.

INVESTMENT PERFORMANCE

Alleghany reported net investment income for the second quarter and first six months of 2018 of $126.3 million and $250.4 million, respectively, an increase of 24.2% and 15.3%, respectively, from the corresponding 2017 periods. The increases in net investment income in the second quarter and first six months of 2018 from the corresponding 2017 periods reflect increases in dividend income resulting from an increase in equity holdings in the portfolio and higher interest income. The increases in net interest income primarily reflect higher yields on short-term investments and floating-rate debt securities, and higher income from funds withheld, partially offset by the impact of the sale of PacificComp as of December 31, 2017.

In addition, net investment income in the second quarter and first six months of 2018 reflects higher partnership income at AIHL. AIHL’s partnership income in the first six months of 2018 includes a one-time $12.9 million increase in the carrying value of AIHL’s limited partnership interests in certain subsidiaries of Ares Management LLC, as of March 15, 2018. Partnership income in the second quarter and first six months of 2017 includes a $12.6 million charge on AIHL’s equity investment in Ares. The charge on AIHL’s equity investment in Ares reflected our share of a one-time

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payment recorded by Ares related to an acquisition by its affiliated entity. In connection with this acquisition, Ares agreed to make certain transaction support payments to the sellers of the acquired entity.

Financial statement total return⁴ on investments was 1.4% for the second quarter of 2018, compared with 1.8% for the second quarter of 2017.

OTHER FINANCIAL INFORMATION

As of June 30, 2018, Alleghany had 14,994,679 shares of its common stock outstanding, compared with 15,390,500 shares of its common stock outstanding as of December 31, 2017. During the first six months of 2018, Alleghany repurchased an aggregate of 403,623 shares of its common stock in the open market for $236.1 million, at an average price per share of $584.96. In June 2018, the Alleghany Board of Directors authorized, upon completion of its previously announced program, the repurchase of additional shares of common stock, at such times and prices as management determines to be advisable, up to an aggregate of $400.0 million. As of June 30, 2018, Alleghany had $527.1 million remaining under both share repurchase authorizations.

In February 2018, the Alleghany Board of Directors declared a special dividend of $10 per share for stockholders of record on March 5, 2018. On March 15, 2018, Alleghany paid dividends to stockholders totaling $154.0 million.

Additional Information

Concurrent with the issuance of today’s earnings press release, Alleghany has posted a financial supplement to its website, www.alleghany.com, containing additional schedules that provide further detail pertaining to Alleghany’s financial results.

Additional information regarding Alleghany’s 2018 second quarter and first six months 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 June 30, 2018 (the “Form 10-Q”), to be filed with the U.S. Securities and Exchange Commission (the “SEC”) on or about the date hereof. The Form 10-Q and the financial supplement will be available on Alleghany’s website at www.alleghany.com. The Form 10-Q will also be available 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.

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About Alleghany Corporation

Alleghany Corporation (NYSE-Y) owns and manages 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; and CapSpecialty, Inc. (referred to herein as “CapSpecialty”), an underwriter of commercial property, casualty and surety insurance coverages.

Alleghany’s subsidiary Alleghany Capital Corporation (referred to herein as “Alleghany Capital”) engages in and oversees strategic investments and acquisitions. Alleghany Capital’s investments are categorized as either industrial businesses or non-industrial businesses. The industrial businesses are: (i) Bourn & Koch, Inc., a manufacturer/remanufacturer of specialty machine tools and supplier of replacement parts, accessories and services for a variety of cutting technologies (referred to herein as “Bourn & Koch”); (ii) R.C. Tway Company, LLC (dba and referred to herein as Kentucky Trailer), a manufacturer of custom trailers and truck bodies for the moving and storage industry and other markets; (iii) WWSC Holdings, LLC, a structural steel fabricator and erector (referred to herein as “W&W|AFCO Steel”); and (iv) Wilbert Funeral Services, Inc., a leading provider of products and services for the funeral and cemetery industries and precast concrete markets (referred to herein as “Wilbert Funeral Services”). The non-industrial businesses are (i) IPS-Integrated Project Services, LLC, a technical service provider focused on the global pharmaceutical and biotechnology industries (referred to herein as “IPS”), and (ii) Jazwares, LLC, a global toy, entertainment and musical instrument company (referred to herein as “Jazwares”). For additional information about Alleghany Capital Corporation, please visit www.alleghanycc.com.

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, operating earnings, operating earnings per diluted share and operating earnings before income taxes, which are “non-GAAP financial measures.” The presentation of these financial measures is not intended to be considered in isolation or as a substitute for, or superior to, financial information prepared and presented in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Also, note that these measures may be different from non-GAAP financial measures used by other companies, limiting their usefulness for comparison purposes. A discussion of Alleghany’s calculation and use of these financial measures is provided below.

Underwriting profit represents net premiums earned less net loss and loss adjustment expenses and commissions, brokerage and other underwriting expenses, all as determined in accordance with U.S. GAAP and does not include net investment income, change in the fair value of equity securities, net realized capital gains, other than temporary impairment losses, noninsurance revenue, other operating expenses, corporate administration, amortization of intangible assets and 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 reinsurance and insurance 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.

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A reconciliation of underwriting profit to earnings before income taxes is presented below.

Operating earnings and operating earnings per diluted share represent net earnings attributable to Alleghany stockholders and earnings per diluted share, respectively, excluding (on an after-tax basis) change in the fair value of equity securities, net realized capital gains, other than temporary impairment losses and amortization of intangible assets, all as determined in accordance with U.S. GAAP. Alleghany uses operating earnings and operating earnings per diluted share as supplements to net earnings attributable to Alleghany stockholders and diluted earnings per share, respectively, the most comparable U.S. GAAP financial measures, to provide useful additional information to investors by highlighting earnings and diluted earnings per share attributable to its performance exclusive of changes in the fair value of equity securities, realized capital gains or losses, impairments and amortization of intangible assets.

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Reconciliations of operating earnings and operating earnings per diluted share to net earnings attributable to Alleghany stockholders and diluted earnings per share, respectively, are presented below.

Operating earnings before income taxes is a non-GAAP financial measure for our non-insurance operating subsidiaries and investments in the Alleghany Capital segment. Operating earnings before income taxes represents noninsurance revenue less all operating expenses, and does not include: (i) amortization of intangible assets; (ii) change in the fair value of equity securities; (iii) net realized capital gains; (iv) other than temporary impairment (“OTTI”) losses; and (v) income taxes. Because operating earnings before tax excludes income taxes, change in the fair value of equity securities, net realized capital gains, OTTI losses, and amortization of intangible assets, it provides an indication of economic performance that is not affected by investment activity, levels of effective tax rates or levels of amortization resulting from acquisition accounting. Alleghany uses operating earnings before income taxes as a supplement to earnings before income taxes, the most comparable GAAP financial measure, to evaluate the performance of certain of its non-insurance operating subsidiaries and investments. A reconciliation of operating earnings before income taxes to earnings before income taxes is presented above in “Segment Results-Alleghany Capital.”

In prior filings, Alleghany has used adjusted EBITDA as a non-GAAP financial measure for its non-insurance operating subsidiaries held by Alleghany Capital. Alleghany believes that operating earnings before income taxes is a more useful non-GAAP financial measure, as it reflects: (i) ongoing capital expenditures through the inclusion of depreciation expense (a component of other operating expenses) and (ii) ongoing levels of debt through the inclusion of interest expenses.

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Forward-looking Statements

This release contains disclosures, which may be deemed “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “may,” “will,” “expect,” “project,” “estimate,” “anticipate,” “plan,” “believe,” “potential,” “should” or the negative versions of those words or other comparable words. Forward-looking statements do not relate solely to historical or current facts; rather, they are based on management’s expectations as well as certain assumptions and estimates made by, and information available to, management at the time. These statements are not guarantees of future performance. These forward-looking statements are based upon Alleghany’s current 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. Factors that could cause these forward-looking statements to differ, possibly materially, from that currently contemplated include:

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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 we have no control; changes in our plans, strategies, objectives, expectations, or intentions, which may happen at any time at our discretion; and other factors discussed in Alleghany’s 2017 Form 10-K. All forward-looking statements speak only as of the date they are made and are based on information available at that time. Alleghany does not undertake any obligation to update or revise any forward-looking statements to reflect subsequent circumstances or events.

For more information, please contact:

Kerry Jacobs

Alleghany Corporation

212-508-8141

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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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