Plan for the key deadlines: October and September dates you cannot ignore
International sellers face four important USA compliance points this September: improved IRS online tools, the 15 October 2026 filing deadline, Kentucky’s removal of its 200-transaction nexus test, and stricter U.S. Customs and Border Protection checks for Importers of Record.
Use this checklist to protect your filings, sales tax registrations, inventory movements and cash flow.
Act now: the four deadlines and changes to track
Here is the short version:
- 15 October 2026: Final extended filing deadline for eligible 2025 federal return extension filers.
- 15 October 2026: Deadline for qualifying foreign-owned U.S. LLCs to file Form 5472 with a pro forma Form 1120 when Form 7004 was filed on time.
- 1 August 2026: Kentucky removed its 200-transaction economic nexus test.
- 18 September 2026: CBP may void Importer of Record numbers linked to inaccurate or incomplete Form 5106 data.
Do not treat these as isolated administrative updates. Each one affects how you file, pay, register or move goods in the United States.
Use IRS online tools to control your compliance records
The IRS has encouraged taxpayers, businesses and tax professionals to use its online services in IR-2026-102.
For international businesses, these tools can reduce delays and give you a clearer record of your federal tax position.
Open and review your Business Tax Account
Eligible businesses can use the IRS Business Tax Account to access certain federal tax information. Available features depend on your entity type and user role.
You may be able to:
- View business information held by the IRS.
- Check account balances and payment history.
- Make federal tax deposits and balance-due payments.
- Access tax transcripts.
- Obtain an EIN verification letter.
- View tax compliance reports.
- Access certain notices and letters.
- Manage authorised users.
The account is available to several business structures, including partnerships, S corporations, C corporations and other eligible organisations. Access may be limited depending on your role.
Keep your user permissions controlled. This reduces the risk of missed notices or unauthorised account changes.
Use Tax Pro Account for authorisations
Tax professionals can use the IRS Tax Pro Account to manage certain Power of Attorney and Tax Information Authorisation requests.
Where available, clients may review, approve and electronically sign authorisation requests through their own IRS online account. This can speed up access to information needed for filing and compliance work.
Other useful IRS tools include:
Use only IRS.gov when signing in. The IRS does not initiate contact by email, text message or social media to request personal or financial information. Do not click suspicious links or share your account credentials.
File by 15 October: an extension does not extend payment
The IRS has reminded 2025 federal return extension filers to submit their returns as soon as possible rather than waiting until 15 October 2026.
The central rule is simple:
An extension gives you more time to file. It does not give you more time to pay.
If tax was due by the original deadline, interest and applicable penalties may continue to apply when payment is late. Review your estimated liability now and arrange payment through the appropriate IRS channel.
Eligible individual taxpayers may also use IRS Free File through 15 October 2026 where their adjusted gross income is $89,000 or less. Free File Fillable Forms may be available to taxpayers above that threshold.
Pay particular attention to foreign-owned U.S. LLC filings
A foreign-owned U.S. LLC may have a Form 5472 reporting obligation. This commonly applies where reportable transactions take place between the LLC and a foreign or domestic related party.
For a calendar-year foreign-owned U.S. LLC:
- The 2025 filing package was generally due on 15 April 2026.
- A timely Form 7004 can extend the filing deadline.
- The extended deadline is 15 October 2026.
- The filing package generally includes Form 5472 and a pro forma Form 1120.
If your LLC has a Form 5472 obligation and Form 7004 was filed by the original deadline, complete the package before 15 October.
The IRS states that late filing of Form 5472 can result in a $25,000 penalty per return. The penalty may be reduced to $5,000 where reasonable cause applies, but you should not rely on penalty relief. Build the filing into your compliance timetable.
Review the official IRS Form 5472 guidance and confirm the exact obligation for your entity.
Remove Kentucky’s obsolete transaction trigger
Kentucky has removed its 200-transaction economic nexus test for remote retailers and marketplace providers.
The change took effect on 1 August 2026 under House Bill 757. Sellers should now focus on the $100,000 gross sales threshold for Kentucky sales rather than using 200 transactions as a separate economic nexus trigger.
Apply the new Kentucky review process
Complete these steps:
- Recalculate Kentucky sales. Review current-year and prior-year gross sales into Kentucky.
- Remove the obsolete transaction trigger. Do not register solely because you exceeded 200 Kentucky transactions.
- Check the $100,000 threshold. Determine whether your Kentucky gross sales exceed the applicable threshold.
- Review marketplace data. Include the relevant sales information from platforms and marketplace providers.
- Reassess existing registrations. If you registered only because of the old transaction count, confirm whether another obligation still applies.
The change does not mean every seller can cancel a Kentucky registration automatically. Inventory, employees, other physical presence and specific marketplace obligations may require a separate review.
Read Kentucky’s official guidance for full details.
Check your Importer of Record status before 18 September
U.S. Customs and Border Protection has been reviewing Importer of Record numbers. If your Form 5106 data is inaccurate or incomplete, CBP may void your number on 18 September 2026.
An Importer of Record number is essential for clearing goods through U.S. customs. A voided number can delay shipments, disrupt your supply chain and create cash flow problems.
Verify that your legal name, address, entity type and tax identification details on file with CBP are current and match your official records.
If you use a customs broker, confirm that your records match their filings. Discrepancies between your data and your broker’s data are a common cause of compliance issues.
Act before 18 September to avoid unnecessary disruption.
Build a September review checklist
Use this simple checklist to stay on track:
- Confirm your IRS filing status and any outstanding balance.
- File any extended 2025 federal returns before 15 October 2026.
- Complete Form 5472 and pro forma Form 1120 for qualifying foreign-owned LLCs.
- Review Kentucky sales against the $100,000 threshold.
- Verify your Importer of Record data with CBP before 18 September 2026.
- Update your internal compliance calendar with all relevant dates.
These actions are straightforward but time-sensitive. Taking them now protects your U.S. market access and avoids costly penalties.
