Tuesday, September 15, 2026 is a major tax day. If any of these apply to you, act before Tuesday:

1. Q3 2026 estimated tax — third installment due

If you pay your taxes quarterly (self-employed, freelancer, or not enough withheld from other income), the third installment for 2026 is due September 15. Individuals use Form 1040-ES; corporations deposit their third installment as well.

2. Extended S-corp and partnership returns

If your S corporation or partnership filed an extension back in March, September 15 is the final filing deadline:

- S corporations: Form 1120-S

- Partnerships: Form 1065

3. Partners and shareholders: watch for your K-1

As these entity returns go out, K-1s go out with them — keep yours. You'll need it for your individual return before the October 15 extension deadline.

The next step is simple: pay or file before Tuesday. Don't wait until the last minute.

Need help? Tamazirth offers a free first consultation — call (646) 651-2449.

The Arabic version of this reminder is on the Abrith blog: https://abrith.com/