Unclaimed income tax refunds totaling almost $1.4 billion may be waiting for an estimated 1.2 million taxpayers who did not file a 2015 Form 1040 federal income tax return, according to the Internal Revenue Service. To collect the money, these taxpayers must file their 2015 tax returns with the IRS no later than this year’s tax deadline, Monday, April 15th. The IRS owes almost 16 million dollars to Nevada taxpayers.