[ by Melanie Gretchen ] A distinguished Wall Street financier, who has been serving as director and vice chairman for private equity giant Apollo Global Management, has resigned from the firm after just 3 years.  Guggenheim Partners, an upstart Wall Street firm, hired Henry Silverman, 71, to serve as vice chairman of the firm's investment management business. Silverman's Tenure at Apollo. Henry joined his close friend Leon Black, who runs Apollo, in 2009.  At the time, it appeared to be part of an effort by the PE firm to boost its senior management ranks as it prepared for its IPO and its rapid expansion into new businesses.  The following year, in November, Apollo hired Marc Spilker, former president at Goldman Sachs. As Vice Chairman at Guggenheim, ... Silverman will run Guggenheim's investment management business - which last month entered into exclusive negotiations to acquire the bulk of Deutsche Bank‘s asset management business.  The deal, if completed, would add some $500 billion in assets to Guggenheim’s money management unit. Silverman's Earlier Wall Street Career. During his distinguished career, Mr. Silverman has worked with Steve Ross, former CEO of Time Warner, and corporate raider Saul Steinberg.  Mr. Silverman perhaps is best known for building the 1990s-era conglomerate Cendant, which combined hotels, rental cars, a real estate brokerage firm, and tax services into a corporate monolith, before splitting up the company into 4 separate businesses. For further details, go to [Dealbook, 3/8/12].