Lou -- you lose the right to claim any losses on any stock if you sell it and then repurchase that/ or similar stock back within 30 days - That means if you want those future carryforward losses to offset gains down road you cannot repurchase that same instrument or simular . The MJ flippers are gonna mess up huge there IMHO as they are playing russian roulette and won't be able to take losses to offset gains made Hence they'll have to pay taxes on All gains but won't be able to write-off Any losses if flipped within that 30 day period