2026 year-end checklist
Year-end planning for marketplace sellers and DTC e-commerce brands.
- By Dec 31
Count and value ending inventory, including goods at FBA and 3PL warehouses.
- By Dec 31
Review state-by-state sales against economic nexus thresholds and register by each state's deadline. Some states expect registration right away, while Texas allows until the first day of the fourth month after you cross.
- By Dec 31
Run S corp payroll and make Solo 401(k) employee deferrals.
- By Dec 31
Buy needed equipment and software and place it in service.
- January 2027
Download every Form 1099-K and reconcile it to gross sales, refunds, and fees.
- Feb 1, 2027
Issue Forms 1099-NEC to freelancers and unincorporated agencies paid $2,000 or more in 2026. Card and payment-app payments are reported on 1099-K instead.
- Feb 1, 2027
Annual Connecticut sales tax filers: file Form OS-114 for 2026, due this day because January 31 is a Sunday. Fourth-quarter and December returns for quarterly and monthly filers are due the same day.
- Mar 15, 2027
To elect the PET for 2026, Connecticut S corps and partnerships check the box on a timely filed Form CT-1065/CT-1120SI and file Form CT-PET, or extend both to Sept. 15, 2027. An extension gives more time to file, not to pay, and electing entities generally must make estimated payments.
- By return due date
Make the S corp's employer 401(k) contribution.
Dates assume a calendar-year taxpayer. Some items require plan documents or elections that only your advisor or plan provider can complete.
Run this checklist with a tax advisor
In a consultation, we look at your sales by state, Forms 1099-K, and last return, estimate whether an S corp and Solo 401(k) could lower your tax, and tell you where you may need to register.