Facebook shares [FB 33.64 -4.5918 (-12.01%) ] plunged more than 13 percent on Monday, falling below the $38 price of the initial public offering, in the social network's second day of trading as a public company. The stock sank without the full support of the company's underwriters, leaving some investors down nearly 25 percent from where they were Friday afternoon. Facebook's debut was beset by problems, so much so that the Nasdaq said on Monday it was changing its IPO procedures.
