Facebook, which had priced its IPO at $38 a share, saw its stock slump as low as $17.55 in September and was trading 30 percent below its initial offering price before yesterday’s results. Concern about Facebook’s ability to shift to mobile has weighed on the company’s shares since its $16 billion IPO, the largest technology offering on record.Even with the decline, the Menlo Park, California-based company traded at 115 times earnings as of yesterday’s close, more expensive than 98 percent of the companies in the Standard & Poor’s 500 Index, according to data compiled by Bloomberg.Mobile PushMobile ads, which made up 30 percent of revenue in the first quarter, will soon account for more than half of advertising dollars, Zuckerberg said on a conference call. The number of mobile users expanded 51 percent to 819 million during the quarter. The total number of Facebook members was 1.15 billion, compared with 1.11 billion in the earlier period.“This quarter represents a strong validation that we’re effectively navigating the shift to mobile,” David Ebersman, Facebook’s chief financial officer, said in an interview. “All the investments we’ve been making in the business have been paying off.”
