Employer benefits plans are deliberately dense. A Summary Plan Description runs dozens of pages of legal boilerplate around a handful of numbers that actually matter to you. Almost nobody reads it cover to cover, so almost nobody catches the gap between what the plan offers and what they're actually claiming. That gap is real money, and it's the reason Marmot exists.
Unclaimed 401(k) match
If your employer matches contributions up to some percentage of salary and you contribute less than that, the unmatched portion is gone for good — it doesn't carry over. Research consistently finds this hits lower earners harder than higher earners, which is part of why Marmot doesn't pre-target any income bracket: the assumption that "only broke grad students miss the match" is wrong.
Employer HSA seed
Many health plans deposit a fixed amount into your HSA every year regardless of whether you contribute yourself — seed money you get just for being enrolled in the right plan. If you skipped HSA enrollment, or didn't realize the seed existed, that deposit never happened.
ESPP discounts
Employee stock purchase plans typically sell shares at a discount to market price, sometimes using a "lookback" that prices off whichever date was cheaper. Not participating means skipping a discount that, in most plans, is close to a guaranteed return the moment shares are sellable.
Expiring stipends
Learning & development budgets, wellness stipends, home-office allowances — these usually reset every year on a clock nobody reminds you about. Unused, they don't roll over. They just expire.
Idle cash
Not an employer benefit, but the same shape of problem: money sitting in a 0%-yield checking or savings account well beyond what you need for a buffer. We flag it as missed yield — we don't tell you what to do with it.
Why completeness is what matters
Any single item on this list is a nice find but not, on its own, a reason to keep an app open. The reason Marmot is worth using is the sweep — checking every category against your actual plan and your actual payroll in one pass, something no one has ever done for you before, for free or otherwise.