Why September Is the Real Deadline for Year-End Tax Planning
Most people think tax planning season starts in December. By then, they’re sipping cocoa, trying to make last-minute moves before the year ends. The truth? If you wait until December, you’ve already missed some of the biggest opportunities.
September is the real deadline. Here’s why.
More Time = More Options
The earlier you plan, the more tools are on the table. By September, you can still:
Shift income and expenses in a way that fits your long-term goals.
Set up or max out retirement accounts — like SEP IRAs, Solo 401(k)s, or cash balance plans. These take paperwork and time, not a December rush.
Run a cost segregation study on rental property to unlock accelerated depreciation. That’s not something you can call in on December 29th.
Tax planning isn’t just about plugging in numbers. It’s about designing a strategy while the year is still in motion.
Real Estate Investors: Why September Is Critical
1. Bonus Depreciation Is Back at 100%
Thanks to the new tax bill, you can deduct the full cost of qualifying property this year if placed in service after january 19th, 2025. A $500,000 rental could mean $125,000+ in deductions with a cost segregation study. That’s real cash flow, not just paper numbers.
2. Short-Term Rental Loophole
If you own an STR, your hours matter. The IRS looks closely at material participation. Documenting hours now — not scrambling at year-end — can be the difference between passive losses you can’t use and massive deductions you can.
3. Repairs vs. Improvements
September is the perfect time to review what you’ve spent so far. Painting, patching, fixing appliances? Those may be deductible now. New roof, major remodel? Likely capitalized. A little classification makes a big difference in this year’s return.
Business Owners: Moves to Lock In Now
1. Entity Structure Pivots Under the OBBB
The “One Big Beautiful Bill” permanently set the 20% QBI deduction and shifted other rules. For some, S-Corp election saves thousands. For others, partnership flexibility wins. Waiting until tax season to review structure is too late.
2. Retirement Planning
Maxing contributions can shelter significant income, but accounts take time to open and fund. Start now, and your April self will thank you.
3. Expense Timing
You have the chance to time purchases, defer or accelerate income, and line up deductions. These calls are strategic, not last-minute receipts in a shoebox.
Final Thoughts
Tax planning isn’t a December activity. It’s a September discipline. When you start early, you get to use the full toolkit: bonus depreciation, entity strategies, retirement plans, and more.
The choices you make this month could mean thousands saved on your 2025 return.
If you’re not sure where to start, this is the season to sit down with your CPA/EA and run the numbers. Better to feel in control now than to be surprised in April.