According to the IRS, there is around $1.1 billion in unclaimed tax refunds for 2014 (whoa, that’s a lot of money just sitting around). They estimate half of these refunds are greater than $847.
In order to claim your refund you must file your 2014 tax return no later than Tuesday, April 17, 2018. Otherwise all of that money goes back to the U.S. Treasury.