There is no statute of limitation on civil tax fraud in the US. There is a limitation on criminal tax fraud, but for example, filing a false return to evade tax

There is no statute of limitation on civil tax fraud in the US. There is a limitation on criminal tax fraud, but for example, filing a false return to evade taxes (such as by not reporting cryptocurrency related capital gains) is a civil matter and the IRS is unrestricted in being able to attempt to collect the correct amount of tax at any point in time. edit: see https://www.law.cornell.edu/uscode/text/26/6501 https://www.law.cornell.edu/uscode/text/26/6501 for the exceptions.