Spilker, a 20-year Goldman Sachs (GS) vet who most recently served as co-head of investment management, received $48.9 million in 2010 compensation from Apollo — including $20.65 million worth of restricted stock and $28.1 million in stock options. He also has an annual base salary of $2 million, which was pro rated for 2010.

The second-highest on Apollo’s compensation list for 2010 was James Zetler, managing director of capital markets, who made over $25 million. Firm founder and CEO Leon Black came in third with $8.9 million.

Still no official word on when Apollo will actually go public. Once it goes, it would become the fourth major U.S. private equity firm to do so — following The Blackstone Group (BX), Fortress Investment Group (FIG) and Kohlberg Kravis Roberts & Co. (KKR) Rumors persist that both The Carlyle Group and TPG Capital could be next in line.

Apollo’s filing also provided updated performance data for its private equity funds. What follows are net internal-rates-of-return (IRRs) for four Apollo private equity funds through year-end 2010, excluding a $14.67 billion vehicle raised in 2008 (which reports a book value of around $11.7b on $7.78b in calldowns):

• Apollo VI (2006): 10% net IRR (4% as of 12/31/09)
• Apollo V (2001): 45% (46%)
• Apollo IV (1998): 9% (8%)
• Apollo III (1995): 12% (11%)