The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F COVER PAGE

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OMB Number:3235-0006
Expires:Oct 31, 2018
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hours per response:23.8

Report for the Calendar Year or Quarter Ended:03-31-2021
Check here if Amendment  Amendment Number:
This Amendment (Check only one.):  is a restatement.
  adds new holdings entries.
Institutional Investment Manager Filing this Report:
Name:ALLEGHANY CORP /DE
Address:1411 Broadway
34th Floor
New York, NY  10018
Form 13F File Number:028-01590

The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:
Name:John F. Shannon
Title:Manager
Phone:(212) 508-8119
Signature, Place, and Date of Signing:
/s/ John F. ShannonNew YorkNY05-07-2021
[Signature][City, State][Date]
Report Type (Check only one.):
X13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager are reported in this report.)
  13F NOTICE. (Check here if no holdings reported are in this report, and all holdings are reported by other reporting manager(s).)
  13F COMBINATION REPORT. (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are reported by other reporting manager(s).)
Form 13F Summary Page
Report Summary:
Number of Other Included Managers:4
Form 13F Information Table Entry Total:93
Form 13F Information Table Value Total:3,123,579
(thousands)
List of Other Included Managers:
Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect to which this report is filed, other than the manager filing this report.
[If there are no entries in this list, state “NONE” and omit the column headings and list entries.]
No.Form 13F File NumberName
2028-10508RSUI Indemnity Company
3028-06459Alleghany Insurance Holdings LLC
4028-15020Transatlantic Reinsurance Company
5028-16393Roundwood Asset Management LLC