Steven Lawrence Rattner (born July 5, 1952) is an American investor, media commentator, and former journalist. He is currently chairman and chief executive officer of Willett Advisors, the private investment firm that manages billionaire former New York mayor Michael Bloomberg's personal and philanthropic assets. He began his career as an economic reporter for The New York Times before moving to a career in investment banking at Lehman Brothers, Morgan Stanley, and Lazard Freres & Co., where he rose to deputy chairman and deputy chief executive officer. He then became a managing principal of the Quadrangle Group, a private equity investment firm that specialized in the media and communications industries.

In 2009, Rattner was named lead adviser to the Presidential Task Force on the Auto Industry. He has also been an economic analyst for MSNBC's Morning Joe, and as a contributing opinion writer for The New York Times op-ed page.

Rattner was born to a Jewish family in Great Neck, New York, the son of Selma and George Rattner. His father was the president of a small paint company and a playwright who produced several Off-Broadway plays; his mother was an architecture preservationist and vice president of the Victorian Society of America. He attended local public schools in Great Neck. Rattner received his A.B. with honors in economics from Brown University in 1974 and was awarded the Harvey Baker Fellowship. While at Brown, he served as editor-in-chief of The Brown Daily Herald in 1973.

Upon graduating from Brown, Rattner was hired in Washington, D.C., as a news clerk to James Reston, New York Times columnist and former executive editor. After a year, he moved to New York as a reporter to cover business and energy; there he became friends with colleague Paul Goldberger. In 1977, he was transferred back to Washington to cover the energy crisis.

At age 27 he became the paper's chief Washington economic correspondent. He became close friends with Arthur Ochs Sulzberger Jr., who was then the Times publisher. He concluded his service to The New York Times with two years in London as its European economic correspondent.

At the end of 1982, Rattner left The New York Times and was recruited by Roger Altman to join the investment bank Lehman Brothers as an associate. After Lehman was sold to American Express in 1984, he followed his boss Eric Gleacher and several colleagues to Morgan Stanley, where he founded the firm's communications group. In 1989, after Morgan Stanley filed for an initial public offering, he joined Lazard as a general partner and with Lazard colleagues advised on numerous deals for large media conglomerates such as Viacom and Comcast. Alongside Felix Rohatyn, Rattner became Lazard's top rainmaker in the 1990s. Michel David-Weill named him the firm's deputy chairman and deputy chief executive in 1997.

In March 2000, Rattner and three Lazard partners, including Joshua Steiner, left the firm and founded the Quadrangle Group. They initially focused on investing a $1 billion media-focused private equity fund. Early investors in Quadrangle included Sulzberger, and Mort Zuckerman. Headquartered in the Seagram Building, Quadrangle grew to manage more than $6 billion across several business lines, including private equity, distressed securities, and hedge funds. The firm also hosted an annual gathering for media executives called Foursquare, where speakers included Rupert Murdoch and Mark Zuckerberg. In 2008, the firm's asset management division was selected to invest the personal and philanthropic assets of New York Mayor Michael Bloomberg, Rattner's close friend.

Throughout his business career, Rattner has served on several corporate boards, including Cablevision, IAC/InterActiveCorp, and Protection One.