BUZZ-OptimizeRX Corp: Falls on WPP exit
** OptimizeRX down ~15 pct at $9.90 premarket as top investor WPP Plc (Frankfurt: A1J2BZ - news) looks to divest its ~18 pct stake in the digital health messaging firm
** OPRX among biggest pct losers across U.S. markets
** After the bell Mon, co announced proposed sale of 2.1 mln shares by WPP subsidiary in secondary offering led by William Blair and B. Filey FBR
** WPP had made "strategic investment" in OPRX in Sept 2015 and in Mar 2018, according to prospectus filing
** OPRX has 7.2 mln shares of free float (Refinitiv data); offering represents more than 40 days of worth of trading volume
** Stock has risen 146 pct this year, following 94 pct gain in 2017