Filed Pursuant to Rule 433
Registration Statement No. 333-259205

• CUSIP: 78016N4B0

• Trade Date: November 27, 2023 (expected)

• Settlement Date: November 30, 2023 (expected)

• Valuation Date: November 27, 2026 (expected)

• Maturity Date: December 2, 2026 (expected)

• Automatic Call Amount: at least 109.25% of the principal amount  (to be determined on the Trade Date)

• Observation Date: November 28, 2024 (expected)

• Early Redemption Date: December 4, 2024 (expected)

• Term: 3 years, if not automatically called

• Reference Asset: the S&P 500^® Index (SPX)

• Leverage Factor: 150%

• Barrier Level: 70% of the Initial Level

• Percentage Change of the Reference Asset:

• If the Final Level is greater than the Initial Level on the Maturity Date, the Notes will pay at maturity a return equal to the Percentage Change times the Leverage Factor

• Subject to 1% loss of the principal amount for each 1% that the Reference Asset decreases if the Final Level is less than the Barrier Level.

• The Notes will be automatically called for the Automatic Call Amount if the closing level of the Reference Asset on the Observation Date is greater than or equal to the Initial Level.

• The notes are subject to Royal Bank of Canada’s credit risk.

• The notes are not principal protected.

• Your notes are likely to have limited liquidity.

• Please see the following page for important risk factor information.

• Each investor will agree to treat the notes as a callable pre-paid cash-settled derivative contract for U.S. federal income tax purposes, as described in more detail in the product prospectus supplement.

DETERMINING PAYMENT AT MATURITY IF THE

NOTES ARE NOT AUTOMATICALLY CALLED

You will lose 1% of the principal amount for each 1% decline in the level of the Reference Asset. The payment at maturity per $1,000 in principal amount of the notes will be calculated as follows:

$1,000 + ($1,000 x Percentage Change)

In this case, you may lose up to 100% of the principal amount at maturity.

Additional Key Information:

This document is a summary of the preliminary terms of an equity linked note that Royal Bank of Canada will issue. It does not contain all of the material terms of, or risks related to, these notes. You should read the preliminary terms supplement for the notes and the documents described below before investing. In addition, you should consult your accounting, legal and tax advisors before investing.  The preliminary terms supplement for this offering will be provided to you prior to your investment decision, and it may also be accessed here: sec.gov/Archives/edgar/data/1000275/000114036123051107/ef20013956_fwp.htm

The notes are not bail-inable notes under the Canada Deposit Insurance Corporation Act.

You should review the preliminary terms supplement carefully prior to investing in the notes.  In particular, you should carefully review the relevant risk factors set forth therein, including, but not limited to, the following:

• You May Receive Less Than the Principal Amount at Maturity.

• The Notes Do Not Pay Interest and Your Return May Be Lower than the Return on a Conventional Debt Security of Comparable Maturity.

• The Notes Are Subject to an Automatic Call.

• Payments on the Notes Are Subject to Our Credit Risk, and Changes in Our Credit Ratings Are Expected to Affect the Market Value of the Notes.

• There May Not Be an Active Trading Market for the Notes—Sales in the Secondary Market May Result in Significant Losses.

• The Initial Estimated Value of the Notes Will Be Less than the Price to the Public.

• The Initial Estimated Value of the Notes that We Will Provide in the Final Pricing Supplement Will Be an Estimate Only, Calculated as of the Time the Terms of the Notes Are Set.

• Our Business Activities May Create Conflicts of Interest.

• You Will Not Have Any Rights to the Securities Included in the Reference Asset.

• The Payments on the Notes Are Subject to Postponement Due to Market Disruption Events and Adjustments.

The SPX is a product of S&P Dow Jones Indices LLC, a division of S&P Global, or its affiliates (“SPDJI”), and has been licensed for use by Royal Bank of Canada.  Standard & Poor’s^® and S&P^® are registered trademarks of Standard & Poor’s Financial Services LLC, a division of S&P Global (“S&P”); Dow Jones^® is a registered trademark of Dow Jones Trademark Holdings LLC (“Dow Jones”).  The Notes are not sponsored, endorsed, sold or promoted by SPDJI, Dow Jones, S&P or their respective affiliates, and none of such parties make any representation regarding the advisability of investing in the Notes nor do they have any liability for any errors, omissions, or interruptions of the SPX.

RBC Capital Markets is the global brand name for the capital markets business of Royal Bank of Canada and its affiliates, including RBC Capital Markets, LLC (member FINRA, NYSE and SIPC); RBC Dominion Securities Inc. (member IIROC and CIPF); Royal Bank of Canada - Sydney Branch (ABN 86 076 940 880); RBC Capital Markets (Hong Kong) Limited (regulated by the Securities and Futures Commission of Hong Kong and the Hong Kong Monetary Authority) and RBC Europe Limited (authorized by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and Prudential Regulation Authority.) ^® Registered trademark of Royal Bank of Canada. Used under license. All rights reserved.

Royal Bank of Canada has filed a registration statement (including a product prospectus supplement, a prospectus supplement, and a prospectus) with the SEC for the offering to which this document relates. Before you invest, you should read those documents and the other documents relating to this offering that we have filed with the SEC for more complete information about us and this offering. You may obtain these documents without cost by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, Royal Bank of Canada, any agent or any dealer participating in this offering will arrange to send you the product prospectus supplement, the prospectus supplement and the prospectus if you so request by calling toll-free at 1-877-688-2301.