[gamblor956]

If you substantially understate[1] your income (including crypto-exchange income), the statute of limitations on your tax return never starts running. That means the IRS has until the end of time to audit you and assess penalties and back interest.[2]

[1] Currently that means excluding items individually or collectively worth more than 25% of the gross income actually stated on the return.

[2] If your omission of crypto-currency income is within 25% of your actual stated gross income, the IRS only has 6 years to audit you and assess penalties...unless they decide that the omission is a deliberate attempt to evade taxes, in which case the unlimited statute of limitations could apply.