https://www.reuters.com/article/us-usa-taxevasion-crypto/u-s-tax-collectors-urge-owners-of-virtual-currencies-to-pay-back-taxes-file-amended-returns-idUSKCN1UL2DB >The U.S. Internal Revenue Service on Friday said it was sending thousands of letters to taxpayers who failed to report virtual currency transactions, saying they may owe taxes.