@Mike9241
It would not be a casualty loss, it would be a theft loss. Theft losses are also not deductible for tax years 2018 through 2025 unless that occurred due to a federally declared disaster.
I once read a very interesting Tax court case on the concept of theft loss versus investment loss. The gist of the case was that the taxpayer owned a painting which he purchased as an expensive master work, but which later turned out to be a forgery. He wanted to deduct the loss as a theft loss, because that allows immediate deduction of 90% of the loss, instead of taking it as an investment loss, where the deduction is limited to the amount of your capital gains for the year plus $3000. In other words, in this particular case, the theft loss allowed a bigger and more immediate deduction. The tax court ruled that in order to have a theft, you must have a thief who benefits from the theft. The court found that in this case, both the previous owner and the art gallery that sold the painting to the taxpayer believed in good faith that the painting was authentic, and any forgery or misrepresentation had occurred so long ago that there was no identifiable thief, and therefore, there was no deductible theft loss.
@Gohard777
applying this logic to cryptocurrency, it would appear that if someone is the victim of a pump and dump scheme, where they invest in cryptocurrency, and the founder disappears with all the money a few days later, that would be a theft loss that is non-deductible under current law. But if the investment firm is legitimate and just badly run, then it can be treated as an investment loss.
But as I said above, your investment is not worthless until the bankruptcy proceedings are concluded, and the court determines whether you get any restitution. When the case is closed, and the restitution is final, whatever it is, then you will have a declarable investment loss.
