Kirkland & Ellis is advising private equity firms The Blackstone Group and Madison Dearborn Partners on a pair of major transactions announced Monday.

In the larger of the two deals, Kirkland—which dominated the buyout rankings of legal advisers for the year’s first quarter—is counseling Madison Dearborn on its proposed $6.25 billion sale of Nuveen Investments to the New York–based Teachers Insurance and Annuity Association–College Retirement Equities Fund Company. If completed, the acquisition will make TIAA-CREF one of the nation’s largest money managers.