Facebook stock fell 3.2% to $19.59 a share, following a 45% drop through October 5th, as a result of a lengthy correspondence with the SEC's corporate finance division that began in February, when Facebook first filed its proposal to go public. The SEC in response requested more in-depth disclosure regarding the risks and complications of the company's mobile platform and inconsistencies with some of the figures and referenced studies in the report. BusinessWeek.