In its 2013 tax guide, the IRS states, “If you find and keep property that does not belong to you that has been lost or abandoned (treasure-trove), it is taxable to you at its fair market value in the first year it is your undisputed possession.”
Check it out:
The Gold Country couple who unearthed at least $10 million worth of 19th century gold coins in their yard last year will probably owe close to half of that sum in federal and state income tax – whether or not they sell the coins.
There is no question that the discovery of the coins is a taxable event. In a famous 1969 decision, a U.S. District Court in Ohio ruled that a “treasure trove” is taxable the year it is discovered. In that case, Cesarini vs. United States, a couple bought a used piano in 1957 for about $15. In 1964, they found $4,467 in old currency inside it.
The court ruled that the money constituted ordinary income in 1964, the year in which they had “undisputed possession” of the funds. It did not qualify for the lower capital gains tax rate because neither the piano nor the currency were sold or exchanged.