This part annoys me; when I would have RSU's vest, my broker would send me a 1095B(?) which plainly lists stock price at time of acquire and time of sale, and the gains, which for RSU's sold at time of vesting is 0
but for some reason I don't understand, they don't report the cost basis to the IRS, just the sale and price at time of acquire, so if you don't file your taxes to fill in that cost basis information, the IRS will cite you as having earned the entire sell cost of the stock!
This fucks up a lot of people new to tech/taxes, and I still haven't been able to find documentation on why they don't file the cost basis for you if they're reporting the sale anyway.