Mamacos, Bysiewicz & Associates LLC
Employee benefit plan audit practice profile, built from plan year 2024 Form 5500 filings.
Last updated · Source data: plan year 2024 Form 5500 filings
How many 401(k) plans does Mamacos, Bysiewicz & Associates LLC audit?
Mamacos, Bysiewicz & Associates LLC was the independent auditor for 14 retirement plan filings in plan year 2024, with clients in 2 states and territories — the #663 practice nationally by volume.
Practice at a glance
| Measure | Value |
|---|---|
| Firm EIN (as filed) | 92-1450991 |
| Retirement plan audits (401(k), 403(b), pension) | 14 |
| All audited filings (incl. welfare plans) | 14 |
| States and territories with clients | 2 |
| National rank by retirement plan volume | #663 of 3,956 |
| National rank, all audited filings (league-table basis) | #711 of 4,052 |
| Average client size (participants) | 307 |
| Largest client (participants) | 612 |
Rankings derived from U.S. Department of Labor Form 5500 filings, plan year 2024. Read the full methodology.
Where does Mamacos, Bysiewicz & Associates LLC audit plans?
| State | Plans audited | Share of practice |
|---|---|---|
| Massachusetts | 13 | 92.9% |
| Georgia | 1 | 7.1% |
Largest concentration: Massachusetts (13 plans). State reflects the plan sponsor’s address, not the firm’s office locations.
What audit opinions does Mamacos, Bysiewicz & Associates LLC issue?
| Opinion type | Filings | Share |
|---|---|---|
| Unmodified (clean) | 14 | 100.0% |
| Qualified | 0 | 0.0% |
| Disclaimer | 0 | 0.0% |
| Adverse | 0 | 0.0% |
As coded on Schedule H. A disclaimer here usually reflects the legacy limited-scope reporting convention (now the ERISA Section 103(a)(3)(C) election), not a failed audit — see the methodology.
Largest plans audited by Mamacos, Bysiewicz & Associates LLC
| Plan sponsor | State | Participants |
|---|---|---|
| John Moriarty & Associates, Inc. | MA | 612 |
| King & Prince Seafood Corporation | GA | 597 |
| Aam 15 Management, LLC | MA | 369 |
| Professional Electrical Contractors of CT, Inc. | MA | 364 |
| Harold Brothers Mechanical Contractors, Inc. | MA | 328 |
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About this profile
This page is generated from public U.S. Department of Labor Form 5500 filings in which Mamacos, Bysiewicz & Associates LLC (EIN 92-1450991) is named as the plan’s independent qualified public accountant. Mamacos, Bysiewicz & Associates LLC did not supply, review, or endorse this information, and inclusion is not a recommendation. Filing data can contain sponsor-entered errors; corrections are welcome via the about page.