Issuer Free Writing Prospectus

Filed Pursuant to Rule 433

Relating to Preliminary Prospectus Supplement dated

March 9, 2021 to Prospectus dated November 6, 2020

Registration Statement No. 333-249950

March 9, 2021

W. R. Berkley Corporation

$400,000,000

3.550% SENIOR NOTES DUE 2052

Issuer:	W. R. Berkley Corporation
Securities:	3.550% Senior Notes due 2052
Security Type:	Senior Unsecured Fixed Rate Notes
Anticipated Ratings*:	Moody’s: Baa1 (Stable) / S&P: BBB+ (Stable)
Minimum Denominations:	$2,000 × $1,000
Trade Date:	March 9, 2021
Settlement Date (T+5)**:	March 16, 2021
Maturity Date:	March 30, 2052
Underwriting Discount:	0.875%
Principal Amount:	$400,000,000
Proceeds (after underwriting discount and before expenses):	$394,852,000
Price to Public:	99.588% of the principal amount, plus accrued interest, if any, from March 16, 2021 to the date of delivery
Spread to Treasury Benchmark:	+130 bps
Treasury Benchmark:	1.625% due November 15, 2050
Treasury Benchmark Yield:	2.272%
Coupon:	3.550%
Yield to Maturity:	3.572%
Interest Payment Dates:	March 30 and September 30, commencing on September 30, 2021.
Optional Redemption – Make-Whole Call:	Then current U.S. Treasury +20 basis points prior to September 30, 2051, six months prior to the maturity date.
Optional Redemption – Par Call:	On or after September 30, 2051, six months prior to the maturity date.
CUSIP; ISIN:	084423 AV4; US084423AV48
Joint Book-Running Managers:	BofA Securities, Inc. Credit Suisse Securities (USA) LLC J.P. Morgan Securities LLC Morgan Stanley & Co. LLC

* Note: A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision, suspension or withdrawal at any time. Each credit rating should be evaluated independently of any other credit rating.

** Note: Under Rule 15c6-1 under the Securities Exchange Act, trades in the secondary market are required to settle in two business days, unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade the notes on any date prior to two business days before delivery will be required, by virtue of the fact that the notes initially settle in T+5, to specify an alternate settlement arrangement at the time of any such trade to prevent a failed settlement. Purchasers of the notes who wish to trade the notes during such period should consult their advisors.

No PRIIPs KID — No PRIIPs key information document (KID) has been prepared as not available to retail in EEA.

No UK PRIIPs KID – No PRIIPs key information document (KID) has been prepared as not available to retail in UK.

The Issuer has filed a registration statement, including a prospectus, with the Securities and Exchange Commission for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the Issuer has filed with the Securities and Exchange Commission for more complete information about the Issuer and this offering. You may get these documents for free by visiting EDGAR on the Securities and Exchange Commission’s website at www.sec.gov. Alternatively, the joint book-running managers will arrange to send you the prospectus if you request it by calling or emailing BofA Securities, Inc., toll-free at 1-800-294-1322 or dg.prospectus_requests@bofa.com, Credit Suisse Securities (USA) LLC at 1-800-221-1037, J.P. Morgan Securities LLC, collect at (212) 834-4533, or Morgan Stanley & Co. LLC, toll-free at 1-866-718-1649 or prospectus@morganstanley.com.