The raise you are refusing
An employer match is a guaranteed, instant 50–100% return — nothing in investing touches that. Yet ~$1,300 per employee is left unclaimed every year on average. Contributing at least to the full match threshold is the closest thing to free money in personal finance. Over 30 years at 7%, an extra $2,250/year becomes roughly $227,000.
Estimates only; check your plan document for vesting schedules and true-up provisions.