I received a 1099-B from my broker which I know is overstating my cost basis by $180. I requested a corrected 1099-B, but have not received one. My choices are to file with the currently incorrect 1099-B and if I ever receive the corrected 1099 then file an amended return or use the numbers that are correct and reduce the cost basis and run the risk of the 1099-B never being corrected. In the second case I will be paying more tax than if a corrected 1099-B is never issued.
