It's a tough post-IPO world out there for Facebook, apparently. Right before more than 271 million additional shares of the company's stock came up for sale today, the company's stock price hit it's lowest point since going public back in May. The stock was trading at $19.69 during the day yesterday and closed just 20 cents higher — slightly over half of the $38 IPO price set by the banks.

According to the Wall Street Journal, there's been a lot of action around those FB shares on the Nasdaq lately: By noon yesterday, traders had moved 94 million shares. That's more than triple the average daily trading volume for Facebook.

Most of those newly available shares belong to early investors who couldn't flip them until certain rules expired today. Those shareholders don't necessarily have to trade their shares, of course, but this is just the first wave of freed stock in the company. WSJ reports more than 1 billion more shares will become available in November and even more will be available for trading next May.