Taxes do go negative for assets decreasing in value. You may deduct any (realized) losses in value from your other (realized) gains. You may also deduct up to $

Taxes do go negative for assets decreasing in value. You may deduct any (realized) losses in value from your other (realized) gains. You may also deduct up to $3k/year of those losses from your income. If you have losses exceeding this amount, you may carry them over into the following year and deduct again. *This is the US tax code, but I suspect many countries operate similarly.