Top 10 Best Retirement Plan Audit Services of 2026

Plante Moran’s core delivery centers on audit planning, transaction and process testing, and documentation tied to the audit engagement letter and management representation letter. Audit teams work from a sponsor-provided participant data census and operational records, then trace results back to plan administration processes that affect financial reporting and compliance outcomes. Deliverables are written for sponsor governance use, with findings mapped to what operations produced, what testing revealed, and what remediation is expected when exceptions occur.

A tradeoff appears in the dependency on clean sponsor data extracts and reconciliation inputs, because testing outcomes hinge on how contribution and remittance records are produced internally. The service fits when a plan administrator can produce timely export files and subject matter staff can support internal control walkthroughs and sampling methodology decisions during fieldwork.

Grant Thornton’s retirement plan audit engagements typically follow a structured audit lifecycle that connects internal control walkthroughs to testing plans and documented results. The firm’s approach emphasizes clear engagement materials like management representation letters and audit engagement letter artifacts that set expectations for evidence, timelines, and responsibilities. For sponsors that need tight audit documentation and repeatable processes year over year, the methodology maps well to how plan teams assemble payroll, participant data, and committee reporting.

A key tradeoff is that Grant Thornton’s documentation-heavy workflow can require active sponsor participation to supply timely plan census, payroll records, and reconciliation support. This fit is strongest when the plan sponsor has a stable internal process for gathering census and remittance data before testing windows start. A better match is also more likely when the sponsor can dedicate a point of contact to respond to evidence requests and confirm corrective action status.

CohnReznick is staffed to support both limited-scope and full-scope retirement plan audits, with repeatable intake, documentation tracking, and evidence management across testing cycles. Engagement deliverables typically include management representation process support, internal control walkthrough documentation, and audit communications that translate testing results into a corrective action plan where issues appear. The firm’s audit execution model is aligned to complex sponsor environments where contribution, eligibility, vesting, and distribution records require structured sampling methodology and clear sign-offs.

A tradeoff is that the audit workflow depends on sponsor-provided data readiness and timely response to information requests, especially for participant census population and reconciliation evidence. A common fit is a plan sponsor running annual audit cadence with multiple recordkeeping sources, where governance around audit-request turnaround and review cycles reduces last-minute churn.

BDO USA delivers retirement plan audit and related compliance services through its national accounting and advisory footprint, with staff assigned to audit fieldwork and technical review workflows. The core capabilities center on ERISA-related audit engagements and financial statement audit support that run through standard audit documentation, representation letters, and findings reporting.

BDO USA also supports Form 5500 preparation and review workflows, including schedule-level focus where needed for plan reporting completeness. For governance teams, BDO USA’s engagement approach emphasizes documented procedures, issue tracking, and a corrective action plan handoff suitable for follow-through after report issuance.

Baker Tilly performs retirement plan audits through ERISA-focused engagements with an emphasis on audit planning, evidence collection, and documented workpaper support. The firm supports both Form 5500 reporting and audit execution workflows that map audit procedures to plan and sponsor records.

Engagement delivery typically centers on an audit engagement letter workflow, management representation letter collection, and a structured path from walkthroughs to audit findings and a corrective action plan. Baker Tilly’s distinctiveness in this category is the combination of audit execution and sponsor reporting coordination across the audit lifecycle rather than standalone Form 5500 preparation.

EisnerAmper provides retirement plan audit services geared toward ERISA reporting requirements and audit deliverables. Engagements are structured around audit engagement letters, management representation letters, and documented audit evidence that supports final conclusions. The firm’s work is oriented toward the annual plan reporting workflow that culminates in Form 5500 support and related schedules. Teams typically coordinate testing inputs with plan operations so that reconciliation and eligibility-related checks map to audit-ready documentation.

Wipfli delivers retirement plan audit services built around ERISA plan reporting workflows and documented audit execution steps. The firm supports engagements that map audit scope to filings like Form 5500 and common schedule components.

Audit delivery coordination focuses on evidence collection, testing documentation, and issuance of the independent qualified public accountant deliverables that plan sponsors expect. Coverage tends to fit organizations that want consistent audit workpapers and clear corrective action paths tied to audit findings.

Withum delivers retirement plan audit services that combine ERISA audit execution with advisory support for common plan issues that surface during testing and reporting. Its teams work across Form 5500 deliverables and the underlying audit workflows that lead to audit findings and corrective action plans.

Withum also supports documentation and evidence handling for engagement letter and management representation letter requirements, which reduces back-and-forth during review cycles. For organizations that need consistent governance across audit and remediation deliverables, Withum’s delivery model maps well to audit engagement structure and stakeholder coordination.

PwC delivers retirement plan audit engagements that map closely to ERISA audit workflows and audit reporting deliverables. The firm’s core capability centers on planning, controls walkthroughs, testing design, and documented audit execution for defined contribution and defined benefit plans.

PwC also supports Form 5500 oriented readiness work that typically feeds the audit process through reconciliation and testing procedures. Large-plan governance and documentation expectations are where PwC’s staffed approach most consistently holds up for complex filings and multi-schedule requirements.

KPMG supports retirement plan audit engagements with a large-firm ERISA audit capability and documented audit methodology for complex plan sponsors. It covers required filings such as Form 5500 and integrates audit work with testing of plan operations and controls.

KPMG typically fits buyers that need consistent lead-partner oversight, multi-location execution, and clear audit documentation for governance and external reporting needs. The offering is best evaluated through engagement scope fit for limited-scope versus full-scope work, plus how audit teams coordinate evidence requests across payroll, recordkeeping, and internal finance functions.