Alternatives to Grant Thornton LLP 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 Grant Thornton LLP for 401(k) plan audits?

Grant Thornton LLP audited 781 retirement plans in plan year 2024 across 40 states and territories (#13 nationally). Closest comparable practices by footprint and volume: RSM US LLP and Crowe LLP; the table below lists 10 firms with linked profiles.

Grant Thornton LLP at a glance

Grant Thornton LLP: plan year 2024 Form 5500 audit engagements (for comparison)
Measure	Value
Retirement plan audits (401(k), 403(b), pension)	781
All audited filings (incl. welfare plans)	816
States and territories with clients	40
National rank by retirement plan volume	#13 of 3,956
Average client size (participants)	5,006
Largest client (participants)	307,988
Largest state concentrations	IL 112 · NY 97 · WI 52

Full profile, including opinion mix and largest audited plans: Grant Thornton LLP.

Audit firms comparable to Grant Thornton LLP

Peer practices by footprint overlap and engagement volume relative to Grant Thornton LLP, plan year 2024
#	Firm	Retirement plans audited	States served	States shared with Grant Thornton LLP	Footprint overlap	Avg. client size
1	RSM US LLP	954	45	39	71%	1,490
2	Crowe LLP	930	40	35	64%	4,730
3	Ernst & Young LLP	519	42	36	72%	21,834
4	BDO USA, P.C.	1,237	45	37	70%	3,242
5	Wipfli LLP	764	42	33	48%	1,071
6	CohnReznick LLP	703	35	32	52%	1,862
7	WithumSmith+Brown, PC	870	39	33	52%	5,491
8	Deloitte & Touche LLP	455	41	35	65%	14,274
9	PricewaterhouseCoopers LLP	351	29	27	67%	13,426
10	EisnerAmper LLP	580	31	29	48%	1,439

Ordered by similarity to Grant Thornton LLP, not by size. Footprint overlap is the share of the two firms’ state distributions that coincide (100% = identical state mix). Candidates: firms with between 157 and 3,905 retirement plan audits (within 5× of Grant Thornton LLP’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

Grant Thornton LLP’s largest states and the comparable firms most active there, plan year 2024
State	Grant Thornton LLP plans	Comparable firms active in the state (plans audited)
Illinois	112	Crowe LLP (155), RSM US LLP (151), Wipfli LLP (73)
New York	97	BDO USA, P.C. (181), EisnerAmper LLP (135), WithumSmith+Brown, PC (127)
Wisconsin	52	Wipfli LLP (306), RSM US LLP (44), BDO USA, P.C. (30)
Pennsylvania	50	BDO USA, P.C. (66), WithumSmith+Brown, PC (66), EisnerAmper LLP (47)
Florida	43	BDO USA, P.C. (66), Crowe LLP (66), WithumSmith+Brown, PC (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 Grant Thornton LLP on two measures: footprint overlap — how closely its distribution of clients across states matches Grant Thornton LLP’s — and volume similarity — how close its engagement count is on a logarithmic scale. Candidates are first limited to a volume band around Grant Thornton LLP’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 Grant Thornton LLP. Filing data can contain sponsor-entered errors; corrections are welcome via the about page.