How Much Does a 401(k) Audit Cost in Washington?

Fee ranges by plan size, and what the Washington audit market looks like in plan year 2024 Form 5500 filings: how many plans are audited, by how many firms, at what plan size, and who does the most of it.

Last updated September 6, 2026 · Source data: plan year 2024 Form 5500 filings

How much does a 401(k) audit cost in Washington?

A 401(k) audit in Washington typically costs $8,000–$18,000 a year — the national range, since fees track plan size, not geography. Washington’s median audited plan (363 participants) falls in the $10,000 – $18,000 band. In plan year 2024, 193 firms audited 1,561 plans sponsored in Washington.

1,561Audited plans in WA

193Active audit firms

363Median plan size (participants)

2.1%Share of U.S. audited plans

Typical 401(k) audit fees for Washington plans

Typical annual 401(k) audit fee ranges by plan size (editorial estimates)
Plan size	Typical fee range	What drives the range
100–249 participants	$8,000 – $14,000	Most first-time audits land here; single payroll and one recordkeeper keep scope tight.
250–499 participantsWA median plan: 363 participants	$10,000 – $18,000	More participant-level testing; still typically one fieldwork cycle.
500–999 participants	$13,000 – $25,000	Larger samples; often multiple payrolls or acquisitions in the mix.
1,000–4,999 participants	$18,000 – $40,000	Complexity-driven: mergers, employer stock, non-standard assets push the top of the range.
5,000+ participants	$30,000+	Multi-entity sponsors, 11-K filers, and hard-to-value assets; fees are bespoke.

Honest labeling: audit fees are not reported in a standardized, reliable field on Form 5500, so these ranges are editorial estimates informed by published fee surveys and engagement quotes — not outputs of our filing dataset, and not specific to Washington. The market figures below are from the dataset. A first-year audit adds roughly 10–25%; an ERISA Section 103(a)(3)(C) election removes roughly 15–40%. See the national cost guide for the full list of fee drivers.

The Washington audit market: the numbers behind a quote

Washington employee benefit plan audit market, plan year 2024
Measure	Washington	United States
Audited retirement plans (sponsor address in Washington)	1,561	72,776
Audit firms with at least one engagement	193	3,956
Audited plans per active firm	8.1	18.4
Median audited plan size (participants)	363	357
Share of plans audited by the ten most active firms	58%	24%
Most active firm’s share of plans	21%	5%

National concentration is the share of all retirement plan engagements held by the ten largest firms nationally; the Washington figure is the share of WA-sponsored plans audited by the ten most active firms in the state. State reflects the plan sponsor’s address, not the audit firm’s offices.

Washington’s median is close to the national median of 357 participants, so the national fee framework applies without adjustment. The market is concentrated: the ten most active firms audited 58% of Washington’s plans, so expect established regional and national practices to compete for your engagement — and to price against each other.

Rankings derived from U.S. Department of Labor Form 5500 filings, plan year 2024. Read the full methodology.

Most active 401(k) audit firms in Washington

Firms ranked by audited retirement plan filings sponsored in Washington, plan year 2024
#	Firm	WA plans audited	Share of state
1	Baker Tilly US, LLP	329	21.1%
2	Clark Nuber P.S.	212	13.6%
3	CliftonLarsonAllen LLP	131	8.4%
4	Sweeney Conrad, P.S.	46	2.9%
5	CBIZ CPAS P.C.	36	2.3%
6	Lee CPA Audit Group	36	2.3%
7	Eide Bailly LLP	30	1.9%
8	Shannon & Associates, LLP	29	1.9%
9	Larson Gross Assurance, PLLC	28	1.8%
10	BDO USA, P.C.	25	1.6%

Top 10 firms shown. Counts are retirement plan filings (401(k), 403(b), profit-sharing, and pension) whose sponsor address is in Washington. Volume measures experience, not quality or price.

Rankings derived from U.S. Department of Labor Form 5500 filings, plan year 2024. Read the full methodology.

The full ranked directory, with market totals, is at 401(k) audit firms in Washington. Each firm profile shows engagement counts, states served, opinion mix, and the firm’s largest audited plans.

How to get a fair 401(k) audit quote in Washington

Quote on the same scope. Tell every candidate whether the plan will elect an ERISA Section 103(a)(3)(C) audit, how many payroll systems it runs, and whether it files Form 11-K. Otherwise the low bid is usually the narrow one.
Engage before spring. Nearly every Washington plan is due July 31 or October 15; firms fill fieldwork calendars first-come, and engagements that start after Labor Day pay for the compression. See the deadline guide.
Shortlist by volume. Ask three to five firms from the table above, or from the state directory, and check each profile for client sizes comparable to yours. A Washington office is optional — audits are performed under national standards from recordkeeper and payroll data — but demonstrated volume is not.
Deliver clean records. Reconciled census, dated remittances, SOC 1 reports, and the certification in hand before fieldwork are the cheapest fee reduction available. The document checklist lists everything the auditor will request.

Washington 401(k) audit cost FAQs

Do 401(k) audits cost more in Washington?

No systematic premium applies. Audit fees are driven by participant count, plan complexity, and record quality rather than the sponsor’s location, and most engagements are performed remotely. Washington’s median audited plan had 363 participants in plan year 2024, versus 357 nationally, which places a typical Washington plan in the $10,000 – $18,000 editorial fee band.

How many firms audit 401(k) plans in Washington?

193 audit firms signed at least one audit of a retirement plan sponsored in Washington in plan year 2024, covering 1,561 audited plans (2.1% of the U.S. total). The ten most active firms accounted for 58% of those plans; the rest were spread across 183 other firms.

Which firm audits the most 401(k) plans in Washington?

Baker Tilly US, LLP audited 329 Washington retirement plans in plan year 2024, the most of any firm and 21% of the state’s audited plans. Clark Nuber P.S. (212) and CliftonLarsonAllen LLP (131) ranked second and third. Engagement volume signals experience, not quality; each firm profile shows opinion mix and client sizes.

401(k) audit cost in other states

Same fee framework, different market. Each page carries the state’s audited plan count, active firms, median plan size, and most active auditors from plan year 2024 filings.