What public Form 5500 filings show about the Mammoth Underground LLC 401(k) plan — and how to find and check your own account.
Mammoth Underground LLC (EIN 02-0646474) reports MAMMOTH UG 401(K) PLAN on its most recent Form 5500, with $3.8M in plan assets across 116 active participants. Form 5500 is the annual report employers file with the U.S. Department of Labor for their retirement plans, and it’s public.
See the full Mammoth Underground LLC filing — schedules, fees, and providers.
Mammoth Underground LLC’s Form 5500 doesn’t separately disclose a recordkeeper we can confirm. The firms named on its Schedule C are service providers — which can include investment managers, trustees, and auditors, and are not necessarily the company that runs your account. To find who runs your 401(k), check your enrollment paperwork or a recent statement, or ask Mammoth Underground LLCHR for the recordkeeper’s name and login.
