You can't depreciate assets that don't lose value over time or that you're not currently using to generate income. Collectibles such as art, coins or souvenirs. According to the Internal Revenue Code, “collectibles are subject to a special and exceptionally high tax rate on long-term capital gains of 28%. While the underlying political rationale may logically apply to sports cards, there is nothing in the law that specifically identifies or defines sports cards as “collectibles”.
The relevant law, IRC §408 (m) (,), contains a general provision that defines a collection object as “any other tangible personal asset specified by the Secretary”. Due to the large gaps created by this legal ambiguity, the application of this discretionary power is usually determined by the taxpayer's particular use of the asset.