December 18, 2019

Kerry J. Jacobs
Senior Vice President and Chief Financial Officer
Alleghany Corporation
1411 Broadway, 34th Floor
New York, New York 10018

       Re: Alleghany Corporation
           Form 10-K for the Fiscal Year Ended December 31, 2018
           Filed February 20, 2019
           File No. 001-09371

Dear Ms. Jacobs:

       We have limited our review of your filing to the financial statements
and related
disclosures and have the following comments. In some of our comments, we may
ask you to
provide us with information so we may better understand your disclosure.

       Please respond to these comments within 10 business days by providing
the requested
information or advise us as soon as possible when you will respond. If you do
not believe our
comments apply to your facts and circumstances, please tell us why in your
response.

       After reviewing your response to these comments, we may have additional
comments.

Form 10-K for the Fiscal Year Ended December 31, 2018

Management's Discussion and Analysis of Financial Condition and Results of
Operations
Comment on Non-GAAP Financial Measures, page 69

1.    The title of your non-GAAP financial measure "operating earnings before
income taxes"
      is confusingly similar to that of a GAAP performance measure used by many
companies.
      Please represent to us that in future filings and earnings releases you
will change the title
      of this measure. See Item 10(e)(1)(ii)(E) of Regulation S-K.
Alleghany Capital Segment Results, page 96

2.    In future filings, please reconcile from the GAAP earnings before income
taxes to the
      non-GAAP operating earnings before income taxes consistent with the
guidance in
      Question 102.10 of the Non-GAAP Financial Measures Compliance and
Disclosure
      Interpretations.
 Kerry J. Jacobs
FirstName Corporation
Alleghany LastNameKerry J. Jacobs
Comapany18, 2019
December NameAlleghany Corporation
December 18, 2019 Page 2
Page 2
FirstName LastName
Notes to Consolidated Financial Statements
Note 1: Summary of Significant Accounting Principles
(b) Investments, page 129

3.       It appears from your disclosure in the first paragraph on page 130
that you utilize a
         retrospective approach in applying the effective interest method for
changes in
         prepayment estimates for your mortgage- and asset-backed security
investments. Please
         tell us why you do not appear to account for at least some portion of
changes in
         prepayment estimates using a prospective approach, given that it
appears from the tabular
         disclosure on page 112 that approximately 24% of your investments in
mortgage- and
         asset-backed securities are not of "high credit quality." Reference
for us the authoritative
         literature you rely upon to support your accounting.
Note 9. Income Taxes, page 161

4.       Please tell us each of the individual components of the 18.1% and
32.0% benefits in
         your "other, net" reconciling item in your rate reconciliations for
2018 and 2017,
         respectively. In addition, tell us your consideration for disclosing
those items that
         account for more than 1.05 percentage points of your effective tax
rate in 2018 and 1.75
         percentage points in 2017 as stipulated in Rule 4-08(h)2) of
Regulation S-X.
5.       You disclose in the last paragraph on page 161 that your effective tax
rate in 2017
         includes tax benefits from taxable losses arising from Hurricanes
Irma, Harvey and
         Maria. Please tell us how the tax benefits from these catastrophes
impact your effective
         tax rate in 2017 and reference for us the authoritative literature
your rely upon to support
         your position. In this regard, it appears that these events
contributed to pre-tax income in
         2017 being less than that in 2016, but it also appears that any
differences between tax
         deductions taken on your return in 2017 and your GAAP loss reserves
associated with
         these catastrophes would be temporary differences that do not impact
your overall
         effective tax rate.
Financial Statement Schedules
Schedule III - Supplemental Insurance Information, page 187

6.       Please represent to us that in future Forms 10-K you will present the
required information
         separately for each of your segments as stipulated in Rules 7-05(c)
and 12-16 of
         Regulation S-X.
       In closing, we remind you that the company and its management are
responsible for the
accuracy and adequacy of their disclosures, notwithstanding any review,
comments, action or
absence of action by the staff.

      You may contact Mark Brunhofer at (202) 551-3638 or Bonnie Baynes at
(202) 551-
4924 with any questions.
 Kerry J. Jacobs
Alleghany Corporation
December 18, 2019
Page 3



FirstName LastNameKerry J. Jacobs    Sincerely,
Comapany NameAlleghany Corporation
                                     Division of Corporation Finance
December 18, 2019 Page 3             Office of Finance
FirstName LastName