It's an asset like anything else, so AFAIK same profit and loss rules apply. For a business that means yes, you can. For individuals that means no, you can't,

It's an asset like anything else, so AFAIK same profit and loss rules apply. For a business that means yes, you can. For individuals that means no, you can't, unless there's a special exception such as losing your cash in a federally declared disaster. If you're both and the assets are mixed (e.g. operating budget and retirement account are both kept under your mattress), I imagine the IRS would presume the cash was personal and it'd be difficult to argue otherwise. I'm not an accountant but have studied basic tax law. I only briefly Googled to make sure I'm not patently misrepresenting things, though.