Facebook stock at half-off, drops below $20 a share

Facebook (s FB) stock has dropped to around $20 a share, almost half its IPO price. The social networking company has seen its valuation tumble to around $38 billion (according to Yahoo Finance). The stock market has soured on social networking stocks including Zynga (s ZNGA) which now trades for $2.71 a share and has a market capitalization of $2.08 billion.