401(k) glossary
·
Administration
Entry date
Short definition
An entry date is the day an employee who has met the plan’s eligibility requirements can start participating. By law it can be no later than six months after eligibility is met or the first day of the next plan year, whichever comes first.
What an entry date is
The plan document sets the entry dates. Common choices are immediate (the day eligibility is met), monthly, quarterly, or semiannual, such as January 1 and July 1. An employee who satisfies the age and service requirements joins on the next entry date.
Why it matters to employers
Entry dates decide when you owe an employee the chance to enroll and, in a plan with automatic enrollment, when deferrals have to begin. Fewer entry dates mean fewer enrollment cycles to run but a longer wait for new hires. Missing someone’s entry date is a common operational error, and the fix is usually an employer-paid contribution.
Example
A plan requires age 21 and one year of service and has entry dates of January 1 and July 1. An employee hired on March 10, 2026 completes a year of service on March 10, 2027 and enters the plan on July 1, 2027.
Common mistakes
Pairing a one-year service requirement with a single annual entry date, which can make employees wait longer than the law allows.
Making a rehired former participant wait for the next entry date. In most cases they re-enter right away.
Having no payroll or HR alert when an employee becomes eligible.
Sources
U.S. Code (govinfo.gov): 26 U.S.C. 410: Minimum participation standards (https://www.govinfo.gov/content/pkg/USCODE-2023-title26/html/USCODE-2023-title26-subtitleA-chap1-subchapD-partI-subpartB-sec410.htm), retrieved 2026-11-11 eCFR (National Archives): 26 CFR 1.410(a)-4: Maximum age conditions and time of participation (https://www.ecfr.gov/current/title-26/chapter-I/subchapter-A/part-1/section-1.410(a)-4), retrieved 2026-11-11 Internal Revenue Service: 401(k) plan fix-it guide: Eligible employees weren’t given the opportunity to make an elective deferral election (https://www.irs.gov/retirement-plans/401k-plan-fix-it-guide-eligible-employees-werent-given-the-opportunity-to-make-an-elective-deferral-election-excluding-eligible-employees), retrieved 2026-11-11
General information, not legal or tax advice.
