Public companies must apply securities laws and accounting rules to their dealings in cryptocurrencies and other digital assets, the SEC’s chief accountant said.

Companies must be able to document that the digital assets they buy, sell, and trade exist and who they are trading with, the Securities and Exchange Commission’s Wesley Bricker told finance and accounting executives at the American Institute of CPAs’ annual banking conference Sept. 17.

“Distributed ledger technology and digital assets, despite their exciting possibilities, don’t alter...