CSMS 66377541·Operational·September 29, 2025·View on csms.cbp.gov ↗

Harmonized System Update (HSU) 2536

Plain-English explanation

CSMS 66377541 is a U.S. Customs and Border Protection (CBP) Cargo Systems Messaging Service bulletin (operational), published on September 29, 2025. It carries the official CBP guidance brokers and importers must follow for the topic — "Harmonized System Update (HSU) 2536". CSMS messages are the operational layer between Commerce determinations and at-the-border collections: when Commerce publishes a new rate, scope ruling, or instruction, CBP turns it into a CSMS that ACE/ACS systems and brokers act on.

Message body

Full text as published by U.S. Customs and Border Protection

CSMS # 66377541 - Harmonized System Update (HSU) 2536 U.S. Customs and Border Protection sent this bulletin at 09/29/2025 09:41 AM EDT Cargo Systems Messaging Service CSMS # 66377541 - Harmonized System Update (HSU) 2536 Harmonized System Update (HSU) 2536 was created on September 25, 2025, and contains 19 Harmonized Tariff Records and 86 ABI records. HSU 2536 includes the European Union (EU) Executive Order tariff updates and Mushroom Assessment Increase. For more information on the EU Tariff changes please see guidance issued in CSMS # 66336270 and/or Federal Register Notice: Implementing Certain Tariff-Related Elements of the U.S.-EU Framework on an Agreement on Reciprocal, Fair and Balanced Trade ( FRN ). For more information on the Mushroom Fee Increase please see USDA AMS Mushroom Assessment Increase Questions regarding the European Union Updates should be directed to Trade Remedy at traderemedy@cbp.dhs.gov . Questions or concerns with the Harmonized System Update should be directed to the HTS admin @ HTSadmin@cbp.dhs.gov. Related Message Number(s): CSMS # 66336270 Update your subscriptions, modify your password or e-mail address, or stop subscriptions at any time on your Subscriber Preferences Page . You will need to use your e-mail address to log in. If you have questions or problems with the subscription service, please contact subscriberhelp.govdelivery.com . This service is provided to you at no charge by U.S. Customs and Border Protection . Privacy Policy | GovDelivery is providing this information on behalf of U.S. Department of Homeland Security, and may not use the information for any other purposes. Powered by Privacy Policy | Cookie Statement | Help

Frequently asked questions

What is CSMS 66377541?

CSMS 66377541 is a U.S. Customs and Border Protection (CBP) Cargo Systems Messaging Service bulletin titled "Harmonized System Update (HSU) 2536". CSMS bulletins are the operational instructions CBP issues to brokers, importers, and ACE filers covering rate changes, system updates, scope guidance, and other day-to-day customs-operations changes.

When was CSMS 66377541 published?

CBP published CSMS 66377541 on September 29, 2025. The bulletin's instructions are typically operative as of the publication date unless the body specifies a different effective date.

Is the CBP CSMS the legally binding instruction?

Yes — for at-the-border filing and entry collection. CSMS messages translate Commerce's Federal Register determinations into operational CBP instructions that ACE/ACS systems and brokers execute. The Federal Register notice is the underlying legal authority; the CSMS is the operational implementation. Both should be read together when reconciling a rate or scope change.

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