#solo-401-k
One-participant 401(k) plans for self-employed individuals, contribution limits, and Roth options
Terminating a 401(k), SEP, or SIMPLE IRA requires 100% vesting, full asset distribution, and a final Form 5500 due seven months after the last payout.
Extended your 2025 return? You can still open and fund a SEP IRA by October 15, 2026 (September 15 for S corps and partnerships) and deduct up to $70,000 — but Solo 401(k) elective deferrals for 2025 are gone for good.
34% of U.S. small business owners have no retirement plan, and more than 80% of a typical owner's net worth sits inside the business. This guide compares the SEP IRA, Solo 401(k), and SIMPLE IRA at 2026 limits ($72,000, $24,500 deferral, $17,000), explains the SECURE 2.0 credits worth up to $5,000 a year for three years, and gives a five-step plan to start saving this quarter.
The IRA contribution limit rises to $7,500 for 2026 — the first base increase since 2023 — plus a new $1,100 catch-up at 50+. Learn who qualifies, how it stacks with Solo 401(k) and SEP, and how freelancers can capture the extra room before April 15, 2027.
EPCRS gives small business 401(k) sponsors three ways to fix plan mistakes — self-correction with no fee, no filing, and no IRS contact through the third plan year for significant errors, a voluntary filing with IRS approval, or a negotiated closing agreement on audit — with standard fixes for late deferral deposits, missed eligible employees, plan loan failures, and missed RMDs.
TrumpIRA.gov, a Treasury-run IRA marketplace launching January 1, 2027, will list providers capped at a 0.15% expense ratio with no account minimums and connect eligible savers to a Federal Saver's Match of up to $1,000 a year — a 50% match on the first $2,000 contributed. Here is how it fits alongside a SEP-IRA or Solo 401(k), and why accurate books determine the contribution you can actually make.
In 2026 a Solo 401(k) lets a self-employed owner shelter up to $72,000 ($83,250 with the ages 60–63 super catch-up) across a $24,500 employee deferral and a 25%-of-compensation employer contribution. This guide covers the two-bucket math, the new mandatory Roth catch-up for W-2 wages over $145,000, first-year vs. ongoing deadlines, and the $250,000 Form 5500-EZ filing trigger.
A Solo 401(k) with voluntary after-tax contributions lets self-employed owners shelter up to $72,000 in 2026 — or $83,250 with the age-60-to-63 catch-up — by converting after-tax dollars to Roth with no income limits. Here's how the three contribution buckets work, a worked example at $150,000 of net earnings, and what your plan document must allow.
A QLAC lets you move up to $210,000 — the 2026 SECURE 2.0 lifetime limit — from a traditional IRA, SEP-IRA, or 401(k) into a deferred annuity the IRS excludes from RMD calculations until payments start, as late as age 85. Here are the rules, a worked example, and the break-even math showing when to skip it.
Starting January 1, 2026, SECURE 2.0's Section 603 requires workers 50 and older with over $150,000 in prior-year FICA wages from the same employer to make 401(k) catch-up contributions — $8,000 standard, $11,250 for ages 60–63 — as after-tax Roth. Plans without a Roth option must amend by December 31, 2026 or bar catch-ups entirely; W-2 S-corp owners are in scope while K-1 partners are not.
For 2026 the IRS caps total 401(k) contributions at $72,000 versus a $24,500 employee deferral limit; business owners can convert the after-tax gap between the two into a Roth account tax-free using the mega backdoor Roth strategy.
Compare the 2026 Solo 401(k) and SEP-IRA limits side by side — when each plan wins, how the SECURE 2.0 super catch-up adds $11,250 for ages 60–63, the mega-backdoor Roth strategy for after-tax conversions, the 20% versus 25% Schedule C calculation, and the Form 5500-EZ filing required once plan assets cross $250,000.
