401(k) Plan Administration in California

California has 40,117 retirement plans with 25 or more participants, with about 14.6 million participants between them — and in most of them the employer is the one legally responsible for running the plan. The recordkeeper holds the money. The advisor picks the funds. Unless the plan document names someone else, the employer is the plan administrator, and that is where the fiduciary responsibility sits. Admin316 takes that role: appointed in writing as your ERISA 3(16) plan administrator and 402(a) named fiduciary, running the compliance calendar and signing and filing the Form 5500.

We are an independent ERISA administrator, working with plan sponsors since 1997. We sell no investment products and take no commissions, so we work alongside whichever recordkeeper, payroll provider and advisor a California employer already uses.

California retirement plans by the numbers

Source: U.S. Department of Labor Form 5500 and 5500-SF filings, plan year 2024 (the most recent year whose filing deadlines have all passed), retirement plans with 25 or more participants at the start of the plan year, counted once per employer ID and plan number, by the sponsor’s mailing state. Timeliness is based on each return’s original filing date; late counts include only returns the DOL has received. Compiled by Admin316 from DOL data downloaded September 30, 2026.

California’s retirement mandate: CalSavers and your 401(k)

• California requires every employer that averaged at least one California employee during the previous calendar year to do one of two things: sponsor a qualified retirement plan, such as a 401(k), 403(b), SEP or SIMPLE IRA, or facilitate CalSavers, the state’s auto-IRA. Businesses whose only employees are the owners, and government, religious and tribal employers, are exempt.
• Employers that already sponsor a qualified plan are exempt, but they must still report that exemption through the CalSavers employer portal. Newly covered employers have until December 31 of the year they receive their mandate notice.
• Penalties under Government Code §100033(b) are enforced by the Franchise Tax Board: $250 per eligible employee if the employer still hasn’t complied 90 days after the first notice, then an additional $500 per eligible employee if noncompliance continues, repeated annually until the employer complies.
• What it means for a 401(k) sponsor: the exemption holds only while the plan is qualified and in place. If the plan is terminated, or a merger leaves a gap in coverage, the employer is back under the mandate. A poorly run plan is also an easy target for an employee who has been told CalSavers is the alternative.

Source: employer.calsavers.com (registration and small-business FAQs); ftb.ca.gov/pay/collections/calsavers; Cal. Gov. Code §100033. This is general information, not legal advice.

California plans in the 2024 filing record

• In plan year 2024, 40,117 retirement plans with 25 or more participants, sponsored by California employers, filed a Form 5500. 36,628 of them (91.3%) are 401(k) plans.
• 7,341 of those plans (18.3%) attached an independent auditor’s report to their 2024 filing (national: 22.8%). A 401(k) plan generally needs this audit once it has 100 or more participants with account balances at the start of the plan year. A plan between 80 and 120 participants can keep filing as a small plan, without an audit, if it filed that way the year before.
• 42.6% filed their 2024 return after the standard seven-month deadline but within a valid extension, which counts as on time (national: 46.0%). For a calendar-year plan, the extension moves the deadline from July 31 to October 15.
• 821 plans (2.0%) were actually late: they filed their 2024 return after the deadline, including any extension (national: 1.9%). This counts only returns the DOL has received so far.
• 2,812 plans (7.0%) list a plan effective date in 2023 or 2024 (national: 6.8%).

Source: U.S. Department of Labor Form 5500 data, plan year 2024.

Already sponsor a plan in California? Look up your plan’s filing record in our free Form 5500 lookup, or book a 20-minute call with the fiduciary who signs the filing.

Where California plans concentrate

City reflects the plan sponsor’s mailing address on the Form 5500, so headquarters cities concentrate. No single city dominates: San Francisco, the largest, accounts for about 6.3% of California’s plans in this population.

What the filing record shows about California plans

California’s late-filing rate runs close to the national average

Of the plan-year 2024 returns the DOL has received from California sponsors in this population, 821 were filed after the deadline, including the extension where one was claimed — 2.0%, against 1.9% nationally. Close to average is not the same as safe: the filings that go late are almost never the ones a sponsor expects. They come in the year a payroll system changed, an entity was added, or the person who quietly owned the calendar left. Separately, 42.6% filed after the standard deadline but by the extended deadline, which is on time, not late. DOL penalties for a late Form 5500 can run up to $2,739 per day with no cap, and the Delinquent Filer Voluntary Compliance (DFVC) Program only helps sponsors who file before the DOL contacts them.

The three findings that cost California sponsors the most

What we take over for a California plan sponsor

How onboarding works

Check your own plan’s filing record first

Before you talk to anyone, look up your own plan. Our free Form 5500 lookup tool shows filing dates against deadlines, participant counts and the years a plan filed late for plans across the country, California included. No login, no cost.

Questions California plan sponsors ask