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Original filing (PDF)20250528140157NAL0017690498001
MAMMOTH UNDERGROUND LLC
Form 5500-SF
FILING_RECEIVED
MAMMOTH UG 401(K) PLAN
401(k) retirement plan
Active participants
116
Accounts w/ balance
73
Plan assets (EOY)
$3.8M
Net assets (EOY)
$3.8M
Plan health score (directional)
83
/ 100
Grade B
Above-average plan
Directional indicator computed from public Form 5500 data — compliance, concentration, cost, vendor stack and participation. Not a fiduciary tool.
Compliance & disclosures
90
Concentration risk
75
Total plan cost
75
Vendor stack
100
Participation health
80
Knocking points off
- No IQPA named; plan is in the 80-120 transition zone — may be filing as small.
- 63% balance-to-active ratio — below typical for a healthy 401(k).
Helping the score
- Concentration not scored — Schedule of Assets PDF not yet parsed for this plan.
- No Schedule C compensation disclosed — likely a small plan or unbundled.
Decision-maker contacts
CFO / Head of HR / Benefits Manager — verified email + LinkedIn for MAMMOTH UNDERGROUND LLC.
Plan sponsor
Name
MAMMOTH UNDERGROUND LLC
EIN
02-0646474
Address
421 W. BONANZA RD. · LAS VEGAS, NV · 89106
Phone
(702) 248-6662
Industry
Constructionsee all
Plan administrator
Same as plan sponsor.
Plan characteristics
Plan number
001
Plan year
2024
Plan year begin
2024-01-01
Tax period
2024-12-31
Filed
2025-05-28
Pension benefit codes
2A · Age/service weighted or new comparability
2E · Profit-sharing
2F · ERISA section 404(c)
2J · 401(k) feature
2K · 401(m) arrangement
2T · Default investment account (QDIA)
3D · Pre-approved plan (master / prototype / VS)
Audit & trust (Schedule H)
Auditor
—
Trustee / custodian
—
Trustee phone
—
Small plan (5500-SF) — Schedule H data not available.
Service providers (Schedule C)
Small plans don't disclose service providersRelated plans
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