Facebook shares continue to slide -

Shareholders might be looking for the head of Mark Zuckerberg stuck on a spike after Facebook shares sank 6.3 percent. You can pick up a second hand one for less than $20.

This time the shares fell because all those who bought them in the overpriced IPO were allowed to get rid of them for the first time.

More than 270 million shares owned by early investors became available for trade yesterday. So far stock is almost 50 percent down from its $38 debut.

Most investors are a little worried about what will happen when more than 1.4 billion additional shares will be eligible for selling by the end of the year will come onto the market. This will happen when Facebook's employees get to cash in stock awards for the first time.

After yesterday, Facebook has lost almost $50 billion, or just under half, of its value since its IPO. The stock, which debuted at $38, fell as much as 7.1 percent to a all-time low of $19.69 before ending the day at $19.87.

With Facebook trading at just under $20, Zuckerberg is now worth $9 billion less that he was after the IPO. And many investors will want their pound of flesh.

After all Zuckerberg has overseen a failed IPO, his stock has been cut in half, and he has ruled over a weak quarter. 

But our prediction is things will get much worse. Facebook is still trading at 40 times its expected 2012 earnings. To put that into perspective Google trades at 16 times and Apple 14.

Our guess is that shares will continue to slide until the company starts making serious money again. Our prediction has been that the share price will settle at about $13, which is the IPO price which we thought was the most reasonable. However that will mean that there are lot of people who have lost their shirts.