08/17/2026
"One month from today, a big one hits: September 15.
That date covers two separate deadlines that both matter a lot, depending on your situation.
If you're an S-Corp or Partnership that filed an extension back in March, September 15 is your filing deadline. No more extensions after this one β miss it, and penalties start stacking up fast, calculated per shareholder or partner, per month late.
If you're self-employed, a business owner, or anyone who pays quarterly estimated taxes, September 15 is also when your Q3 estimated payment is due β covering income earned June through August.
The next 30 days are the time to get ahead of both. If you're on extension, that means getting final numbers to your preparer now, not the week of the 14th. If you're paying quarterly, it means running the numbers on your year-to-date income so you're not guessing.
Waiting until the second week of September to think about either one rarely ends well β for your return or your blood pressure.
If you're not sure which of these applies to you, that's a totally normal question, and a quick call is usually all it takes to find out.
Need help getting ready before September 15? Reach out to Molen & Associates at www.molentax.com."