I don't look at the card board as an investment. I see it as a hobby. I think that's what it was when I first started collecting about 40 years ago. Some people could look at it as an investment.
Here's something to think about. If cards were truly an investment wouldn't the market be strong because of the 'quantative easing" that's going on? That's a lot of $$$ getting pumped into this economy and I don't see the card values sky rocketing with the extra amount of money being thrown into our economy. Do you think this stuff has topped out?
Honestly, I hope the price of cardboard hits the floor so that I can buy the stuff I like and not have to feel like I'm going to have buyers remorse because I bought a slabbed piece of cardboard.