In tax law, a rule disallowing
investors from
deducting more
investment money from their
taxable income than they have actually invested. For example, if one places $10,000 in a
stock and would otherwise derive $15,000 in tax deductions from the investment, the at-risk rule only allows the investor to deduct $10,000. The rule exists to prevent a person from investing in a way that
avoids taxes excessively.