At a glance
- The 2022 SECURE 2.0 Act created the opening for those two business types.
- Employer contributions for the same plan year can be funded until the extended return deadline, Sept. 15 or Oct. 15, 2027, depending on entity type.
- For advisors, April 15, 2027 is the binding date for a client who wants 2026 deferrals, because deferrals cannot be made unless the plan is open by then.
Sole proprietors and disregarded single-member LLCs can open a solo 401(k) for 2026 as late as April 15, 2027 and still fund that year's elective deferrals, according to Ed Slott's IRAHelp. The 2022 SECURE 2.0 Act created the opening for those two business types. A solo plan suits self-employed owners with no employees other than a spouse.
Employer contributions for the same plan year can be funded until the extended return deadline, Sept. 15 or Oct. 15, 2027, depending on entity type. For 2026, elective deferrals cap at $24,500, with catch-ups of $8,000 at age 50 or older and $11,250 at ages 60 to 63. Combined deferrals and employer contributions top out at $72,000, plus catch-ups; the employer piece can reach 20% of adjusted net earnings for unincorporated businesses.
For advisors, April 15, 2027 is the binding date for a client who wants 2026 deferrals, because deferrals cannot be made unless the plan is open by then. The relief covers brand-new plans only: a participant in an existing solo 401(k) cannot make a retroactive elective deferral election.
Reported by The Advisor's Note desk from Ed Slott — IRAHelp. Published . Corrections