Scroll through your 401(k) fund menu and you will find a list of things that behave the way investments behave. Stock funds that go up and down. Bond funds that go up and down slightly less. A target date fund doing a bit of both.
And then there is one option sitting there quietly with a name like "Stable Value Fund" or "Fixed Income Guaranteed Account," and its chart is a straight line going gently upward.
It has never had a down year. It pays noticeably more than a savings account. And you cannot buy it anywhere else, at any price, no matter how much money you have.
That last part is the interesting bit. Stable value funds exist almost exclusively inside employer retirement plans. Walk into a brokerage and ask for one and they will look at you politely.
So what is this thing, why does it work, and what is it quietly costing you? Let's open it up.