Retirement Plans with Most Participants

How Plan Rankings Are Constructed

Ranking retirement plans is more subtle than ranking, say, restaurants or stocks. A "largest" plan is unambiguous when measured by participant count or asset total, both are reported in Form 5500 and audited by an independent accountant once a plan crosses the 100-participant threshold. But a "best" plan is contextual: the right benchmark for a multi-employer pension fund is different from the right benchmark for a single-employer 401(k), and both are different from the benchmark for an ESOP. PlainRetire's ranking pages stick to clearly defined, source-derived metrics, participant counts, plan assets, net contribution, employer contribution as a share of pay, year-over-year asset growth, and surface each metric on its own page so readers can decide which framing is relevant for their question.

Each ranking includes the underlying source (Form 5500 schedule and line item), the plan-year vintage, and a footnote when an aggregate excludes plans with incomplete or amended filings. Where a plan has filed multiple amendments, a sometimes-routine but sometimes-meaningful signal, the ranking uses the most recent accepted filing and notes the amendment count on the plan detail page. This approach lets readers see who is at the top of a particular ladder without conflating different scales of "size" or "growth."

Methodology and Limitations

Rankings are computed against the most recent annual dataset released by the Department of Labor. New plans, terminations, and significant amendments will not appear until the next annual release, which has roughly a seven-month publication lag from plan year end. Plans that file Form 5500-EZ (single-participant plans) are not included in the public datasets and therefore do not appear in PlainRetire rankings. International plans, government plans, and church plans (which are exempt from Title I of ERISA) are similarly outside the dataset and outside these rankings. When evaluating a ranking, consider the universe being compared: a national ranking of 401(k) sponsors will be dominated by Fortune 500 employers, while a state-level ranking will surface regionally significant plans that don't appear in the national list.

Asset and participant counts are reported by the plan sponsor and certified by an auditor for plans above 100 participants. Smaller plans rely on plan-sponsor attestation. Both are subject to standard data-quality caveats: corrections appear as amended filings in subsequent years, and PlainRetire reflects amendments as soon as DOL releases updated datasets.