My broker does similarly, but puts negative amount in proceeds, and zero in cost.
My tax software accepts this, but will not allow a negative amount in cost.
BUT
e-File would not work with negative proceeds on Schedule D. This was a known problem and
IRS suggested a work around to tax software providers so the e-File could go through.
Perhaps that problem has been fixed by now.
Schedule D is supposed to allow a negative proceeds and you should be able to e-File.
@sanash
cc: @Mike9241
