I've been looking into this because I have had 3 crypto accounts hacked and drained. I'm not a professional CPA or Tax person of any kind so please do your own verification. From what I can tell, IRS doesn't allow you to claim a loss from crypto currency theft or hacking etc. However, that doesn't mean you have to claim a profit on the transactions that a hacker did which would happen automatically if you simply uploaded your transactions to a crypto tax calculating company \ website such as Cointracker and Koinly to name a few. If you use Cointracker (not sure about Koinly and other providers), which is recommended by Coinbase, to calculate your crypto taxes, you can review all your transactions and mark as appropriate the transactions that you didn't authorize as lost/stolen. This prevents those transactions from being counted as a profit or a loss. I've got to believe that the IRS must be onboard with this knowing that Cointracker, recommended by Coinbase, is enabling you to do this. Please do your own checking.
