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

Fee ranges by plan size, and what the California 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 California?

A 401(k) audit in California typically costs $8,000–$18,000 a year — the national range, since fees track plan size, not geography. California’s median audited plan (331 participants) falls in the $10,000 – $18,000 band. In plan year 2024, 759 firms audited 8,081 plans sponsored in California.

8,081Audited plans in CA

759Active audit firms

331Median plan size (participants)

11.1%Share of U.S. audited plans

Typical 401(k) audit fees for California 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 participantsCA median plan: 331 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 California. 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 California audit market: the numbers behind a quote

California employee benefit plan audit market, plan year 2024
Measure	California	United States
Audited retirement plans (sponsor address in California)	8,081	72,776
Audit firms with at least one engagement	759	3,956
Audited plans per active firm	10.6	18.4
Median audited plan size (participants)	331	357
Share of plans audited by the ten most active firms	39%	24%
Most active firm’s share of plans	11%	5%

National concentration is the share of all retirement plan engagements held by the ten largest firms nationally; the California figure is the share of CA-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.

California’s median is close to the national median of 357 participants, so the national fee framework applies without adjustment. The market is moderately concentrated: the ten most active firms audited 39% of California’s plans, with the balance spread across 749 other firms — a mix of regional specialists and occasional auditors.

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 California

Firms ranked by audited retirement plan filings sponsored in California, plan year 2024
#	Firm	CA plans audited	Share of state
1	Baker Tilly US, LLP	867	10.7%
2	Pension Assurance LLP	586	7.3%
3	CliftonLarsonAllen LLP	303	3.7%
4	Holthouse Carlin & Van Trigt LLP	280	3.5%
5	Miller Kaplan Arase LLP	257	3.2%
6	WithumSmith+Brown, PC	197	2.4%
7	Lee CPA Audit Group	184	2.3%
8	Armanino LLP	182	2.3%
9	CBIZ CPAS P.C.	170	2.1%
10	BPM LLP	133	1.6%

Top 10 firms shown. Counts are retirement plan filings (401(k), 403(b), profit-sharing, and pension) whose sponsor address is in California. 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 California. 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 California

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 California 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 California 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.

California 401(k) audit cost FAQs

Do 401(k) audits cost more in California?

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. California’s median audited plan had 331 participants in plan year 2024, versus 357 nationally, which places a typical California plan in the $10,000 – $18,000 editorial fee band.

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

759 audit firms signed at least one audit of a retirement plan sponsored in California in plan year 2024, covering 8,081 audited plans (11.1% of the U.S. total). The ten most active firms accounted for 39% of those plans; the rest were spread across 749 other firms.

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

Baker Tilly US, LLP audited 867 California retirement plans in plan year 2024, the most of any firm and 11% of the state’s audited plans. Pension Assurance LLP (586) and CliftonLarsonAllen LLP (303) 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.