An unreversed inclusion generally is a previously included gain.  More specfically, an unreversed inclusion means with respect to any Market-to-market (MTM) stock the excess of the amount of mark to market gain included in gross income with respect to the stock in prior years (including any amount subject to section 1291 during the first year of the election) over the amount allowed as a deduction to the U.S. person with respect to such stock for prior taxable years.