Stephen Schwarzman

When you're the new king of Wall Street, you can count on a decent turnout for your birthday. Stephen Schwarzman, co-founder and CEO of the Blackstone Group, turned 60 in February, and the guest list at his Park Avenue bash in Manhattan was a Who's Who of the business, entertainment and political élite. Yes, that was Vernon Jordan rubbing shoulders with Barry Diller and Cardinal Edward Egan.

Schwarzman's firm makes a pretty penny in a number of finance fields, including real estate and hedge funds, yet carries the most heft for its work in private equity—a force that is remaking corporate America and spreading its influence overseas. Blackstone controls nearly 50 companies, including Vlasic-picklemaker Pinnacle Foods and motelier Extended Stay, accounting for more than $85 billion in sales. Line that up with the Fortune 500 and Blackstone ranks near Home Depot and IBM. By taking companies private and often loading them up with debt, Blackstone and its ilk squeeze value out of businesses while staying shielded from the impatience of the stock market and its prying—some might say pertinent—regulatory eye.

That's why it's a tad ironic that in March Blackstone filed for an initial public offering to sell a small slice of the firm, which has made the hands-on Schwarzman, an arts lover who chairs the Kennedy Center in Washington, a billionaire several times over. Blackstone investors, including pension funds and the über-wealthy, have also done well, earning returns north of 20% a year. Now that's something to celebrate.