
401(k) glossary
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Administration
Summary plan description (SPD)
Short definition
A summary plan description (SPD) is the plain-language document that explains a retirement plan’s rules to participants. ERISA requires the plan administrator to give it to each new participant within 90 days.
What an SPD is
The SPD tells employees, in language they can understand, how the plan works. Department of Labor rules list what it must contain, including:
The plan’s name, sponsor, plan administrator and trustee.
Eligibility rules and when participation starts.
How contributions and vesting work.
When and how benefits are paid, and what could cause a loss of benefits.
The claims and appeals procedure.
A statement of participants’ rights under ERISA.
Timing
New participants: within 90 days after they become covered.
New plans: within 120 days after the plan becomes subject to ERISA.
Changes: a summary of material modifications is due within 210 days after the end of the plan year in which the change was adopted.
Updates: a fully updated SPD every five years if the plan was amended, and every ten years if it was not.
Why it matters to employers
The SPD is the document employees and courts rely on. If it is missing, out of date or inconsistent with the plan document, the plan administrator is exposed in a dispute. A participant who asks in writing for the SPD must receive it within 30 days, and a court can impose a daily penalty on an administrator who does not respond.
Electronic delivery is allowed if you follow the Department of Labor’s electronic disclosure rules.
Common mistakes
Never giving the SPD to new hires because it “lives on the portal” without a proper notice.
Amending the plan and not issuing a summary of material modifications.
Using an SPD from a previous provider after changing plans.
Assuming the provider delivers it. Confirm who sends it and keep proof.
Letting the SPD and plan document say different things about eligibility or vesting.
Sources
eCFR (National Archives): 29 CFR 2520.102-3: Contents of summary plan description (https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XXV/subchapter-C/part-2520/subpart-B/section-2520.102-3), retrieved 2026-11-11 U.S. Department of Labor, EBSA: Reporting and disclosure guide for employee benefit plans (https://www.dol.gov/sites/dolgov/files/EBSA/about-ebsa/our-activities/resource-center/publications/reporting-and-disclosure-guide-for-employee-benefit-plans.pdf), retrieved 2026-11-11 U.S. Code (govinfo.gov): 29 U.S.C. 1021 (ERISA section 101): Duty of disclosure and reporting (https://www.govinfo.gov/content/pkg/USCODE-2023-title29/html/USCODE-2023-title29-chap18-subchapI-subtitleB-part1-sec1021.htm), retrieved 2026-11-11
General information, not legal or tax advice.

