The task of determining how much tax you owe on retirement income is not an easy one, and taxpayers consistently get it wrong. Because of this, the IRS has recently turned its attention to capturing lost funds, and a report released Tuesday by the Treasury Inspector General for Tax Administration cites ways this can be done. Their No. 1 suggestion? Revising the 1099-R form to clarify that a return marked “Taxable amount not determined” requires the taxpayer to determine the taxable amount. The profits resulting from this one small change could be huge. TIGTA found forms listing $107.5 billion in taxable amounts in total that all had a box checked that said “Taxable amount not determined.” It also found forms with distributions totaling $67 billion where the taxable amount was left blank. “This contradictory or absent information can confuse taxpayers, resulting in them reporting the incorrect amounts of retirement income on their tax returns,” the report says.