Strapped for cash, most state governments are turning to unconventional means to increase revenue—and they are finding unclaimed property audits to be an easy target.

“The states’ unclaimed audit activity is at an all-time high, because they are searching for ways to meet their budgets,” says Laura Lane, vice president of the unclaimed property services division at consulting firm The Keane Organization. “They see unclaimed property as a really fluid source for revenue, because it doesn’t involve raising taxes.”

According to the National Association of Unclaimed Property Administrators, U.S. states collectively hold more than $33 billion in unclaimed property—a figure that ...