if you close a short position, or a long position, enter the cost and proceeds as positive numbers,
a loss will show as a negative number in Form 8949 Col (h)
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At tax time, you have the option to summarize your transactions by Sales Category.
IRS requires details to be listed on a Form 8949,
or on your other forms (e.g. consolidated 1099-B) which have the same information and in the same manner as Form 8949.
Either way, if you choose to summarize, you have to mail the transaction details to the IRS within three business days of IRS accepting your e-Filed tax return.(unless you have attached a PDF of the transactions details to your e-Filed return. Last I looked, TurboTax does not offer this feature).
Exception: if you summarize Category A or Category D, Form 8949 is not needed for transactions without adjustments. No mailing is necessary.
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As an active investor, be aware that your category Box A or Box D sales without adjustments do not require Form 8949, so there is no reason to import or key in those transactions.
Instead use the "enter a summary" option to put your numbers on Schedule D Line 1a or Line 8a.
