One of Silicon Valley’s top investors — and a key, early supporter of Mark Zuckerberg’s social network company — won’t stand for re-election at the June 11 annual meeting, Facebook says in an SEC filing. James Breyer has been on the company’s board since 2005. This isn’t a complete surprise: Breyer has been selling Facebook shares at least since October, when he unloaded about $81M of his holdings in the company. Breyer is a board member at News Corp and privately held Legendary Pictures as well as Walmart and Dell. Facebook shares closed Friday at $26.85, well below the $38 IPO price last May but up from the low of $17.55 in September.