Level 1

Sale of Collectibles

We are selling my husband's comic collections via Ebay as part of our retirement. This has been a hobby of his since he was around 10 or 11 years old, and he has been very active with this all his life (Now in late 60's). Since this has been a hobby and not a business, we do not have any idea of what he has paid for 98% of his books. Any suggestions on how to report the basis? 


Also, would it be better to continue to report the sales as "long-term investment of comic collectibles", or would we save on taxes if we made it a business? He is not buying, just selling. Would a business be subject to self-employment taxes, such as Medicare/SS, local transit taxes, property taxes, etc.?


Thank you.