Glossary

Plan sponsor

Employer or business entity that establishes and maintains the retirement plan.

Definition

The plan sponsor is the legal entity (sole proprietorship, LLC, partnership, S-corporation, or C-corporation) that adopted the Solo 401(k) plan document and is responsible for filing Form 5500-EZ each year the filing is required. The sponsor's EIN appears on Form 5500-EZ line 2b.

Why it matters

For IRS Form 5500-EZ, this term helps decide which records, dates, values, or review questions belong in the packet.

How the tool uses it

Solo 5500 treats this as a review signal. The user enters the facts, checks the source-linked explanation, reviews the packet, and files through the official channel when the supported case still fits.

When to check the source

Check the official source when the answer depends on eligibility, late filing relief, official correspondence, valuation, or a fact you cannot verify from your own records.

Source and review date

Last reviewed: . Use the linked source for the official wording behind this term.

Official source: IRS Form 5500-EZ filing notices

Related terms

Plan administratorPerson or entity designated under the plan document to manage day-to-day operations and required filings.Form 5500-EZIRS annual return for one-participant retirement plans (owner-only Solo 401(k), partner-spouse plan, or foreign plan).