On the eve of Facebook’s big IPO, Mark Cuban predicted that the public offering could be the “most important” in history – but not for the reasons you might think. Cuban thought brand excitement would bring in retail investors who wouldn’t read the prospectus, and would then be chewed up by high frequency/algorithmic traders, who would “attack this stock like a pack of wolves.”

Today, with Facebook stock creeping to under half of its initial offering price, Cuban admits that even he lost money trading Facebook stock. Like many others, Cuban expected Facebook stock to bounce upward, which never happened. From a post on Cuban’s blog:

I bought and sold FB shares as a TRADE, not an investment. I lost money. When the stock didn’t bounce as I thought/hoped it would, I realized I was wrong and got out. It wasn’t the fault of the FB CFO that I lost money. It was my fault. I know that no one sells me shares of stock because they expect the price of the stock to go up. So someone saw me coming and they sold me the stock. That is the way the stock market works. When you sit at the trading terminal you look for the sucker. When you don’t see one, it’s you. In this case it was me.

In that same post, Cuban made it clear that he doesn’t begrudge Facebook its high initial offering price, the way many investors now do. He points out that the Facebook CFO was right to price the stock as high as possible, as Facebook ended up raising $10 billion. Cuban blames individual investors and brokers who didn’t read the prospectus for their own losses, and states that no one cares about traders, like himself, who were “hoping for a pop.”