Last Chance to Open a Retirement Plan for 2025:
The September 15 & October 15 Deadline
If your business is on a 2025 tax extension, the window to open and fund a Defined Benefit, Cash Balance, or profit sharing plan is still open, but it closes at your extended deadline. A six-figure deduction is on the table right now. The one thing you cannot do is wait.
Every September, a business owner calls us in the second week of the month, having just seen their final 2025 profit number, asking whether anything can still be done about the tax bill. The answer is almost always yes, and it is almost always urgent. If you filed a tax extension, you are sitting on one of the most powerful and least-used tax tools available, and a deadline that is now measured in days, not months.
The SECURE Act changed the calendar for retirement plans in a way most owners still don't realize. You no longer had to set up a plan by December 31, 2025 to get a 2025 deduction. If your business is on extension, you can establish and fund a plan right now, in late 2026, and still deduct it against your 2025 income. But that flexibility has a hard stop: your extended filing deadline. This is the article for anyone racing that clock.
Your Deadline, by Business Type
The date that applies to you depends on how your business files. For calendar-year businesses on a valid 2025 extension, these are the final dates to both adopt and fund a plan for the 2025 tax year:
| Business Type | Extended 2025 Deadline | Practical "Start By" Date |
|---|---|---|
| S Corporation | September 15, 2026 | Immediately — days remain |
| Partnership / Multi-Member LLC | September 15, 2026 | Immediately — days remain |
| Sole Proprietor / Single-Member LLC | October 15, 2026 | By mid-September at the latest |
| C Corporation | October 15, 2026 | By mid-September at the latest |
| Applies to calendar-year businesses that filed a valid 2025 tax extension. The plan must be adopted and funded before the return is filed, and no later than the extended deadline. Confirm your exact date with your CPA. | ||
Two conditions must both be met by your date. The plan must be formally adopted (signed document, trust established) and it must be funded (the contribution actually deposited into the plan's trust) before you file the return that claims the deduction.
Your September 15 deadline is the tightest. Because a compliant Defined Benefit or Cash Balance Plan takes two to four weeks to design, document, and fund, and most administrators stop accepting new retroactive plans well before the statutory date, the realistic window to start is right now. Every day of delay narrows what is achievable.
How Much Is Still on the Table
The size of the opportunity depends on which plan fits your situation. For a high-income owner, the difference between the options is enormous.
| Plan | 2025 Deduction Potential | Best For |
|---|---|---|
| SEP IRA | Up to $70,000 | Simple, fast, but capped |
| Profit Sharing Plan | Up to 25% of comp, max $70,000 | Owners wanting flexibility |
| Cash Balance Plan | $100,000–$250,000+ | High earners, predictable funding |
| Defined Benefit Plan | Highest available, often $300K+ | Older solo owners maximizing |
| 2025 limits. Defined Benefit and Cash Balance figures are actuarially determined by age, compensation, and years to retirement, and require certification. A SEP IRA established now may limit your ability to also run a DB/CB plan for the same year — coordinate with an actuary first. | ||
Compare the ceilings. A SEP IRA or profit sharing plan caps out at $70,000 for 2025. For an owner in their 50s, a Cash Balance Plan or Defined Benefit Plan is frequently two to four times larger than every alternative combined. That is why, for the right owner, this deadline is worth moving heaven and earth to hit.
How Retroactive Adoption Works
The mechanics are more straightforward than most owners expect. The entire process, from first call to funded deduction, follows four steps.
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Confirm eligibility and run the actuarial illustration
We verify your entity type, extension status, 2025 compensation, and employee census, then produce an illustration showing your exact contribution range and deduction. This takes days, not weeks.
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Adopt the plan document
The plan is drafted and signed with a retroactive effective date of January 1, 2025. Under the SECURE Act, it is treated as established on the last day of the 2025 tax year.
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Open the trust and fund the contribution
A trust account is opened and the 2025 contribution is deposited. Funding must be complete before you file the 2025 return, and never later than your extended deadline.
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File the return and claim the deduction
Your CPA claims the contribution on the 2025 return. We coordinate the timing directly with your accountant so nothing slips.
September 15 is the legal date, but it is not the practical one. A compliant plan needs an actuarial illustration, a custom document, trust setup, and a funded contribution, and each step has a queue behind it in September. Most administrators, including us, stop accepting new retroactive engagements two to three weeks before the statutory cutoff because a rushed plan is a compliance risk nobody should take. Treat the start of September as your real decision point for a September 15 deadline.
Who This Is For
This deadline matters most to a specific kind of owner. If you recognize yourself here, the call is worth making today.
- Owners with a strong 2025 and an extension on file. Consultants, physicians, attorneys, dentists, real estate professionals, and agency owners who saw the profit number and want a deduction to match it.
- Self-employed professionals with variable income. Retroactive adoption lets you decide after you know exactly what the year produced, removing the guesswork that stops many owners from committing in December.
- Owners behind on retirement savings. A retroactive Defined Benefit or Cash Balance Plan captures a year you thought you had already lost.
- CPAs with extension-season clients. Retroactive plan adoption is one of the few genuinely large levers still available for 2025 returns being finalized right now.
"An owner who files on September 15 without exploring this has almost certainly overpaid their 2025 taxes by tens of thousands of dollars. The tool was right there, and the only thing standing between them and it was a phone call made three weeks too late."
What It Looks Like in Practice
Consider an S-corp owner, age 54, with $330,000 of W-2 compensation and a strong 2025, on a valid extension with a September 15, 2026 deadline. Here is what starting the process in the last week of August makes possible.
Nearly $78,000 of federal tax, erased from a bill that was otherwise due, by a plan established weeks after the year had already closed. The only requirement was starting in time.
If you already filed, the retroactive window for 2025 has closed, because the deduction must be claimed on a return filed after the plan is adopted and funded. The good news: you are early, not late, for a 2026 plan, and current-year adoption gives your actuary maximum design flexibility. Let's set up your 2026 plan now.
Frequently Asked Questions
Yes, if your business filed a valid tax extension and has not yet filed its 2025 return. Under the SECURE Act you can adopt a Defined Benefit, Cash Balance, or profit sharing plan up to your extended deadline and treat it as established for 2025 — September 15, 2026 for S corporations and partnerships, October 15, 2026 for sole proprietors and C corporations. The plan must be both adopted and funded before the return claiming the deduction is filed.
The contribution must be deposited before you file your 2025 return and no later than your extended deadline: generally September 15, 2026 for S corporations and partnerships, and October 15, 2026 for sole proprietors and C corporations. Because setup and funding take time, most administrators stop accepting new retroactive plans two to three weeks before the deadline.
A profit sharing plan or SEP allows up to $70,000 for 2025. A Cash Balance or Defined Benefit Plan is actuarially calculated and can allow far more, commonly $100,000 to $300,000 or more for owners in their 40s, 50s, and early 60s. The exact figure requires actuarial certification based on your age, compensation, and years to retirement. Estimate yours here.
Generally no. The extended adoption deadline applies only if you filed a valid 2025 extension. If your original deadline passed without one, the window to establish a plan for 2025 has typically closed. But you are well positioned to establish a plan now for 2026. Confirm your specific situation with your CPA immediately.
Typically two to four weeks, including the actuarial illustration, plan document, and trust setup and funding. With a September 15 or October 15 deadline approaching, starting immediately is essential — waiting until early September for a September 15 deadline is high risk, because most administrators stop accepting new retroactive plans several weeks before the cutoff.
Get Your Free 2025 Deduction Illustration Today
Tell us your age, income, and entity type. Our enrolled actuaries will show you exactly how much you can still contribute and deduct for 2025 before your deadline, at no cost. Then we build it, fast.
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