When an employer receives a reversion of assets from a terminating qualified plan, a § 4980 excise tax of 20% or 50% applies. Here's how it works.

What triggers the § 4972 excise tax on nondeductible employer contributions, how to calculate it, and how carryforward amounts work.

A step-by-step walkthrough of the lost earnings calculation for late 401(k) deposits — the formula, the applicable interest rate, and worked examples.

A practical guide to the seven most frequently seen prohibited transactions under IRC § 4975, including late deposits, self-dealing loans, and plan asset misuse.

A complete reference for Form 5330 filing deadlines by IRC section, how to get an extension, and what happens if you file or pay late.

When a 401(k) plan fails ADP or ACP nondiscrimination testing, a Form 5330 excise tax may be owed under § 4979. Here's what you need to know.

Step-by-step guide to calculating the § 4975 excise tax on late 401(k) participant contribution deposits, including the lost earnings formula.

A plain-English guide to IRS Form 5330 excise tax returns — who must file, which IRC sections apply, and when returns are due.