BlackRock ETF Trust

BlackRock ETF Trust II

Supplement dated September 11, 2026

to the currently effective Statement of Additional Information (the “SAI”)

for each of the funds listed in Appendix A (each, a “Fund”), as amended from time to time

Effective immediately, the following changes are made to each Fund’s SAI:

The fifth paragraph of the section of the SAI entitled “Investment Advisory, Administrative and Distribution Services — Payments by BFA and its Affiliates” is deleted in its entirety and replaced with the following:

In addition, BFA Entities have entered into other contractual arrangements with Intermediaries and certain other third parties that the BFA Entities believe may benefit the business of the BFA Entities or facilitate investment in the Fund or certain Products. Such agreements can include payments by BFA Entities to such Intermediaries and third parties for data collection and provision, technology support, platform enhancement, or educational content, co-marketing and cross-promotional efforts. In certain cases, such payments to Intermediaries are subject to certain minimum payment levels or tiered payments. With respect to certain funds and Products, payments by the BFA Entities may take the form of, among other things, “due diligence” payments for an Intermediary’s review of such funds and Products; payment for providing employee training and information relating to such funds and Products; fees for access (in some cases on a preferential basis) to an Intermediary’s registered representatives, salespersons or other personnel, fees for maintaining an Intermediary’s investor platform, “shelf space” payments for making such funds and Products available on the Intermediary’s platform or fees for providing assistance in promoting the sale of such funds and Products. In such cases, the payments to Intermediaries may be tiered or based on a percentage of the value of the funds and Products held by customers of the applicable Intermediary and may also be subject to minimum payment levels. Payments made pursuant to such arrangements may vary in any year and may be different for different Intermediaries and third parties and may reflect different services provided. As of the date of this SAI, the Intermediaries and other third parties (or their respective affiliates) receiving one or more types of the contractual payments described above include (in addition to FBS and NFS): &Partners, Advisor Credit Exchange, AE Wealth Management, LLC, American Enterprise Investment Services, Inc., Avantax Investment Services, Inc., BNY Mellon Capital Markets, LLC, BNY Mellon Performance & Risk Analytics, LLC, Cetera Financial Group, Inc., Charles Schwab & Co., Inc., Clearstream Fund Centre AG, Commonwealth Equity Services, LLC, Dorsey Wright and Associates, LLC, Dynasty Financial Partners LLC, E*Trade Securities LLC, Envestnet Asset Management, Inc., Equitable Advisors, LLC, iCapital Markets LLC, Interactive Brokers LLC, LPL Financial LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated, MML Investors Services, LLC, Morgan Stanley Smith Barney LLC, Northwestern Mutual Investment Services, LLC, Orion Portfolio Solutions, LLC, Pershing LLC, Raymond James Financial Services, Inc., Riskalyze, Inc., Rockefeller Financial LLC, Sanctuary Wealth Group, LLC, UBS Financial Services Inc., Wells Fargo Clearing Services, LLC and Wells Fargo Advisors Financial Network, LLC. Any additions, modifications, or deletions to Intermediaries and other third parties listed above that have occurred since the date of this SAI are not included in the list.

Shareholders should retain this Supplement for future reference.

Appendix A

SAI-ETF-0926SUP

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