Now, the question isn’t whether Pokémon cards are a good investment, but whether the boom can last. Bubble warning: Not all gains are created equalSome collectors are starting to worry that Pokémon cards are riding a wave that can’t last. One armchair analyst who tracks the Pokémon market has started to see what looks like a classic bubble. Anyone thinking about Pokémon cards as an investment needs to first do their own research and remember that past performance is never indicative of future returns. If it’s for the love of the hobby, vintage cards and thoughtful collecting still make sense.