I called the Turbo Tax experts about this and was eventually referred to this thread. AnnetteB6's post is the best answer. Brokers will need to issue undated tax reporting statements to conform to the revised IRS instructions. Meanwhile editing the values will correct the negative number problem and produce the same correct gain or loss for each edited transaction.
Two new related questions for AnnetteB6 or other tax experts: Since zeroing out the negative numbers in the proceeds column will increase the total proceeds, total proceeds will not match the broker's report to the IRS. Will this cause the return to be rejected by the IRS? Even if it does not, will we have to file an amended return when the broker subsequently issues a corrected 1099B?
