Frontier Communications (NASDAQ: FTR) just completed the biggest acquisition in company history. Subsequently four hedge funds run by billionaires shed all or part of their holdings in the cable, phone, and broadband company.Of course, billionaires aren't infallible, but the actions of Tudor Investment Corp. Baupost Group, Highbridge Capital Management, and Millennium Management, led by billionaires Paul Tudor Jones, Seth Klarman, Glenn Russell Dubin, and Israel Englander, respectively, show how risky a proposition Frontier has become.