Robert Mercer, Bannon Patron, Is Leaving Helm of $50 Billion Hedge Fundbr “We do not consider the personal political opinions and private activities of individual employees when making decisions.”br Steve Yoakum, executive director for Public School Retirement System of Missouri, another Renaissance investor,br said the furor over Mr. Mercer was a “manufactured issue.” He said performance trumped anything else.br Robert Mercer, a billionaire investor and top financial backer of conservative causes, is stepping down as co-chief executive of Renaissancebr Technologies, as the giant hedge fund faces a backlash from some clients who resent Mr. Mercer’s embrace of polarizing political figures.br In letters to investors and to Renaissance staff on Thursday morning, Mr. Mercerbr said he would step down as co-chief executive and as a board member on Jan. 1.br The retirement fund for Baltimore’s police and firefighters, for example, last week askedbr that all of the $33 million it had invested in Renaissance be refunded, said David A. Randall, the retirement fund’s deputy executive director.br “Mercer is now such a controversial figure, that must cause all kinds of difficulties for the company,” saidbr Nick Patterson, a computational biologist at the Broad Institute, who hired Mr. Mercer at Renaissance.