Auditing a Guideline 401(k) plan, now Gusto 401(k)

Is my Guideline plan now Gusto 401(k)?

Probably, if your company runs payroll through Gusto. Gusto’s acquisition of Guideline completed in November 2025, and the product is now called Gusto 401(k) powered by Guideline, with recordkeeping by Gusto Retirement Services, LLC.^[2] Gusto says existing Gusto and Guideline setups stay the same and the plan dashboard is still at my.guideline.com.^[3] Guideline’s own help article on audits for large plans now redirects to Gusto’s help center.^[1]

Not every Guideline plan went to Gusto. Vestwell describes Accrue 401k as “the entity formed to support the Guideline 401(k) plans not part of the Gusto acquisition,” and announced in December 2025 that it would acquire Accrue, with nearly 30,000 plans expected to move to its platform.^[4] If your plan changed provider during the year being audited, the auditor needs records from each provider for the part of the year it held the plan, and the opening and closing balances have to tie across the move.

What does Gusto 401(k) do when your plan needs an audit?

• It tells you. When a plan becomes subject to the audit requirement, Gusto says “you will get an email and a task on your plan dashboard.”^[1]
• It leaves the choice of auditor to you. “You may choose any qualified firm.” Gusto lists some firms other clients have used and says it makes no representations as to their qualifications or suitability.^[1] It suggests engaging a firm before March 31.^[1]
• It gives the auditor an audit package, once you unlock it. The Form 5500 audit task asks for the firm name, the firm’s EIN, the auditor’s name and email. Gusto says “your auditor cannot retrieve the package until you complete the task,” and sends weekly reminders until you do.^[1]
• It does not run the audit. For a plan with 100 or more participants with an account balance, Gusto says it does not manage the Form 5500 audit.^[7] Your own list of tasks includes having the payroll register ready, answering the auditor’s questions, completing compliance tasks on the dashboard and signing the auditor’s representation letter.^[1]
• It files the extension if needed. Gusto Retirement files Form 5558 automatically when it looks like the Form 5500 cannot be filed by the first deadline, and you are responsible for the late-filing penalty if the audit report does not arrive in time.^[1]

Where are the reports your auditor will ask for?

The audit package covers much of the recordkeeper side. When the auditor asks for something by name, this is where Gusto says it lives in the Gusto Retirement administrator dashboard:^[5]

Gusto’s SOC article lists SOC 1 and SOC 2 reports and bridge letters but does not say which Gusto services each report covers.^[6] Ask for the SOC 1 that covers retirement recordkeeping, not only payroll, and a bridge letter if its period ends before your plan year does. Gusto’s documents article has no general distribution report, so ask for distribution and loan detail for the year directly.^[5]

How does payroll affect late-deposit testing on a Guideline plan?

Every audit tests whether employee deferrals reached the plan on time. The rule is that deferrals, and loan repayments, become plan assets on the earliest date they can reasonably be segregated from the employer’s general assets, and never later than the 15th business day of the following month.^[9] The seven business day safe harbor is limited to small plans, so a plan large enough to need an audit is generally held to the first test.^[9]

On Gusto payroll, the timing is fixed by the integration. Gusto says: “The day after the check date, we debit your company for both employee deductions and company contributions,” and invests the funds the following day.^[7] The auditor compares each payroll’s check date with its debit, so the payrolls that stand out are the ones outside that rhythm: a deduction that was missed and made up later, or a correction run after the fact.

On other payroll, nothing is automatic. Gusto says a business with a self-service plan “is responsible for manually uploading payroll reports and making contribution rate updates.”^[8] The deposit date is then whenever your team does that, and a late upload is a late deposit. Keep each payroll’s check date next to its upload date; that pairing is the evidence the auditor tests.

Late deposits are reported on Schedule H line 4a, year after year until fully corrected, including lost earnings.^[10] Gusto Retirement lists late deposits among the situations for which it prepares Form 5330.^[1] The DOL’s Voluntary Fiduciary Correction Program covers delinquent participant contributions and loan repayments.^[11] If you are not sure which year your plan first needs an audit, see how the count of 100 works.

What does Ledgerline audit?

401(k) and 403(b) plans, whichever platform holds them. We’re building an audit firm around those two plan types and booking engagements for the coming season, starting December 2026. The list of requests is the same on every platform; what changes is where each item lives, which is what this page is for. How a Ledgerline audit works, or what a first auditor looks at.

Also on this site: Gusto as your payroll, for any 401(k) provider, Human Interest 401(k) audits, and 401(k) audits by city and recordkeeper.

Frequently asked questions