I don't think that could fly, like every other kind of income, they are counting on you to accurately report taxable gains on the 1040 schedules. The 1099s DO give them a lot more to ask pointed questions about if they think your numbers look funny and pull your file for an audit, though, and you'd very much want to be able to back up whatever you claimed the original purchase price or other basis in the asset was, if they came calling.