The Clark Medal is awarded every two years to an economist under age 40 who has made the most significant contribution to economics. Shleifer was selected for the award for his work examining securities markets and the role of government in regulating markets and in fostering economic growth, according to media reports.

The medal will be awarded at a meeting in January 2000.

Economics Department Chairman Jeffrey Williamson, the Laird Bell Professor of Economics, congratulated Shleifer publicly in a statement on the department's Web page.

"The Harvard Economics Department is simply delighted to learn that Andrei Shleifer has been awarded the John Bates Clark Medal for 1999," Williamson's statement said. "All of us have come to appreciate the extraordinary talent (and charm) that Andrei shares with us every day. We knew the medal belonged to him all along. It sure is terrific to know that the economics community beyond Littauer Center agrees."

Shleifer joins several Harvard professors in winning the award. Others include Martin Feldstein, the George F. Baker Professor of Economics; Zvi Griliches, the Paul M. Warburg Professor of Economics; Hendrik Houthakker, Henry Lee Professor of Economics Emeritus; and Dale Jorgenson, the Frederic E. Abbe Professor of Economics.

Shleifer, who is on leave this year, joined the Harvard faculty in 1991 as a professor of economics. He came here from the University of Chicago, where he was a professor of finance and business economics at the Graduate School of Economics.

Shleifer received a bachelor's degree in mathematics from Harvard in 1982. He received a Ph.D. from the Massachusetts Institute of Technology in 1986.