You Filed On September 15 — What Comes Next
Updated: August 2026 · Industry Advisors · Education, not legal or tax advice.
September 15 is behind you. Q3 estimated tax is paid, confirmations are archived. The next three months are the quiet quarter — no big federal deadline lands until January 15. That makes September 16 through November 30 the ideal window for the decisions that actually move the needle in year one and year two: S-Corp election prep, insurance renewal, and getting the books ready for a clean year-end close.
Week 1 · Books Catch-Up
Between Sept 16 and 30, do the bookkeeping catch-up you have been putting off. Aim for month-of-August fully reconciled by Sept 30. Match every bank line to a category, every credit-card charge to a project, every payment received to an invoice. Flag anything that will not resolve immediately — the November-December sprint gets harder if the September queue is still open.
October · Insurance And License Renewals
- General liability — pull the declarations page. Compare limits to current-year revenue.
- Professional liability / E&O — same.
- Workers' comp — if you added employees, expect a payroll audit at renewal.
- Business licenses — many run on calendar year and lapse December 31. Municipal business tax receipts renew separately from state SoS filings.
- Registered agent — confirm the service is paid through next year in every state where you're registered.
The Q4 compliance checklist covers the full list of October items.
November · The S-Corp Election Decision
November is when to decide whether to elect S-Corp status for the following tax year. The S-Corp election window post walks through the math and the four-month runway to March 15. The first 30 days after election post covers what happens once you file Form 2553.
Retirement Plan Setup By Year-End
Solo 401(k) accounts must be established by December 31 to allow employee-deferral contributions for the current year. SEP IRA accounts can be opened up to your extended tax deadline. Whichever you pick, opening early lets you compute contribution amounts precisely rather than under a deadline crunch.
December · The Year-End Close
Final reconciliation, lock the books, archive. The 12-point year-end housekeeping checklist is the full close-out sequence.
Quick Check
Q1. Q3 is paid. When is the next federal estimated-tax payment due?
Answer: January 15, 2027 (Q4 payment for tax year 2026).
Q2. If your LLC nets ~$75K profit and has not elected S-Corp, when is the decision window?
Answer: November — four months of runway to March 15. Deciding in February is deciding late.
Q3. Do Solo 401(k) accounts need to be established by December 31 or by tax-filing deadline?
Answer: Established by December 31 for employee-deferral contributions. Funded by tax-filing deadline. Different rules.
The Quiet Quarter As A Growth Window
Beyond compliance, September 16 through November 30 is often the best window for structural moves the daily-firefight cadence blocks: revisiting the Operating Agreement, updating your contracts and TOS, filing trademarks, and building the multi-member governance clauses that prevent disputes downstream.
Sources And Further Reading
The Everyday Owner's Blueprint maps the September 16 through December 31 window onto the 12-month calendar with each task's exact date and lead time.
Industry Advisors · 30 Wall Street, New York, NY 10005. Education, not legal or tax advice.
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