Alternatives to WithumSmith+Brown, PC for 401(k) Audits

Peer audit practices selected by overlapping state footprint and similar engagement volume, from plan year 2024 Form 5500 filings. A neutral comparison: no firm pays to appear, and listing is not a recommendation.

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

Which firms are comparable to WithumSmith+Brown, PC for 401(k) plan audits?

WithumSmith+Brown, PC audited 870 retirement plans in plan year 2024 across 39 states and territories (#12 nationally). Closest comparable practices by footprint and volume: CohnReznick LLP and Grant Thornton LLP; the table below lists 10 firms with linked profiles.

WithumSmith+Brown, PC at a glance

WithumSmith+Brown, PC: plan year 2024 Form 5500 audit engagements (for comparison)
Measure	Value
Retirement plan audits (401(k), 403(b), pension)	870
All audited filings (incl. welfare plans)	1,023
States and territories with clients	39
National rank by retirement plan volume	#12 of 3,956
Average client size (participants)	5,491
Largest client (participants)	671,575
Largest state concentrations	CA 197 · NJ 170 · NY 127

Full profile, including opinion mix and largest audited plans: WithumSmith+Brown, PC.

Audit firms comparable to WithumSmith+Brown, PC

Peer practices by footprint overlap and engagement volume relative to WithumSmith+Brown, PC, plan year 2024
#	Firm	Retirement plans audited	States served	States shared with WithumSmith+Brown, PC	Footprint overlap	Avg. client size
1	CohnReznick LLP	703	35	31	65%	1,862
2	Grant Thornton LLP	781	40	33	52%	5,006
3	BDO USA, P.C.	1,237	45	35	62%	3,242
4	Pension Assurance LLP	918	42	34	47%	756
5	Crowe LLP	930	40	35	42%	4,730
6	Caron & Bletzer, PLLC	1,133	41	32	50%	863
7	EisnerAmper LLP	580	31	26	55%	1,439
8	RSM US LLP	954	45	35	40%	1,490
9	Ernst & Young LLP	519	42	35	56%	21,834
10	CBIZ CPAS P.C.	1,616	48	37	56%	2,237

Ordered by similarity to WithumSmith+Brown, PC, not by size. Footprint overlap is the share of the two firms’ state distributions that coincide (100% = identical state mix). Candidates: firms with between 174 and 4,350 retirement plan audits (within 5× of WithumSmith+Brown, PC’s volume). Average client size is the mean beginning-of-year participant count of the firm’s audited retirement plans.

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

Where the footprints overlap

WithumSmith+Brown, PC’s largest states and the comparable firms most active there, plan year 2024
State	WithumSmith+Brown, PC plans	Comparable firms active in the state (plans audited)
California	197	Pension Assurance LLP (586), CBIZ CPAS P.C. (170), BDO USA, P.C. (76)
New Jersey	170	CohnReznick LLP (110), EisnerAmper LLP (90), BDO USA, P.C. (69)
New York	127	CBIZ CPAS P.C. (203), BDO USA, P.C. (181), Caron & Bletzer, PLLC (171)
Texas	67	Crowe LLP (148), BDO USA, P.C. (102), Pension Assurance LLP (48)
Pennsylvania	66	BDO USA, P.C. (66), CBIZ CPAS P.C. (61), Grant Thornton LLP (50)

State reflects the plan sponsor’s address on Form 5500. Each state link opens the full ranked directory for that state.

How these alternatives were selected

Every firm in the dataset with at least 25 retirement plan audits in plan year 2024 was scored against WithumSmith+Brown, PC on two measures: footprint overlap — how closely its distribution of clients across states matches WithumSmith+Brown, PC’s — and volume similarity — how close its engagement count is on a logarithmic scale. Candidates are first limited to a volume band around WithumSmith+Brown, PC’s count (widened only when fewer than 8 firms qualify), then ranked by a weighted score (60% footprint, 40% volume). Ties resolve by volume, then name. The result is deterministic and rebuilds identically from the same filings.

What the score does not measure: audit quality, fees, staffing, industry focus, or fit for your plan. Volume and footprint indicate which firms do this work at comparable scale in the same places; they are a shortlist, not a verdict. Use each profile’s opinion mix and client-size figures, then the questions in how to switch 401(k) auditors to compare on what matters — EBPAQC membership, peer review results, team continuity, and a like-for-like fee.

Comparable-firm tables for other leading practices

Alternatives pages exist for the 25 largest employee benefit plan audit practices by retirement plan volume in plan year 2024.

About this page

Generated from public U.S. Department of Labor Form 5500 filings in which each firm is named as the plan’s independent qualified public accountant. None of the firms shown supplied, reviewed, or endorsed this comparison, and inclusion is neither a recommendation nor a criticism of any firm, including WithumSmith+Brown, PC. Filing data can contain sponsor-entered errors; corrections are welcome via the about page.