Your cryptocurrency exchange may send you a 1099 tax form reporting certain income-based activity. In some cases, this could be rewards or the total volume of your cryptocurrency sales over the year. Unfortunately, this form doesn’t provide all the information you need to fill out your tax return. You need to know when you bought cryptocurrency, how much you paid for it, how long you held it, when you sold it, and how much you sold it for to calculate your capital gains taxes owed correctly.