The U.S. Internal Revenue Service has said it will treat Bitcoin as a form of property for tax purposes, rather than as currency, making it subject to similar rules as stocks and barter transactions. The new rules announced Tuesday appear to be good news for investors, because any gains they make from buying bitcoins will be treated as capital gains, which can mean lower tax rates. But they could also mean that people who spend bitcoins to buy goods and services will have to keep detailed records of those transactions.