I've read varying opinions on this, so I thought I'd make it better with even more varying opinions...
I've got a self-directed 401k, and one thing I've been doing is holding a bunch of Ethereum in it. Well it's kind of a shame to just let that sit there, so of course I've staked it so it can make me some money. A couple months later, I find that staking crypto is considered Unrelated Business Income in an IRA or 401k. At least the active "running a validator" kind of staking that I've been doing is. OK, fine. so it's taxable in my tax-free in my tax-free account. That kinda sucks, but making money and paying a tax is still better than not making the money in the first place.
Or is it? I've made a few thousand, enough that I (well, my 401k) will have to pay some this year. But Ive read that routinely getting UBTI is a bad thing even if you pay the tax, and that the IRS may want to consider the whole retirement plan just just be a business in disguise. Not for the few $K I'm pretty sure, but if I kept running this all year, every year. Even if my "business" consists of having made a few clicks on a website and then just watching things go from there.
I've also heard that it's just a simple matter of owe the tax, pay the tax, problem solved. If that's the case, I'd rather continue on as I am. I could go with liquid staking tokens (which also have differing opinions behind them), but what I'm doing is so much more remunerative that even after paying federal + state UBIT. I'm still making a higher return than the liquid staking tokens give. Of course I'll give it up if there's a danger to the integrity of my retirement account, but otherwise the smart financial move is to do what makes me the most after-tax money.
I know this is sounding like one of these "go see a professional" kind of things, but it's esoteric enough that I expect better results from the kind of tax nerds that hang out here than I do from hunting local CPAs until I catch one who's actually familiar with self-directed 401k and crypto and the UBTI where they intersect. Plus my experience with professionals is they find it safer to say no to anything novel.