Carlyle Group and investors including Swiss bank Pictet & Cie agreed to buy Duff & Phelps for $665.5 million.
The buyers, also including Stone Point Capital and Edmond de Rothschild Group, will pay $15.55 a share, 19% more than Duff & Phelps' closing price on Dec. 28.
The transaction is expected to be completed in the first half, the companies said in a statement Dec. 29.
The group of buyers will help Duff & Phelps continue its international expansion, according to the statement. Revenue at the 80-year-old firm, which also provides financial advisory services, is predicted to rise 17% this year to $465.8 million, the average of analysts' estimates compiled by Bloomberg.
Private equity firm Carlyle last month agreed to buy a stake in energy investor NGP Energy Capital Management for $424 million.
The Duff & Phelps merger agreement provides for a “go-shop” period ending Feb. 8, during which the company can solicit and receive alternative proposals. Duff & Phelps would pay a breakup fee of about $6.65 million if it gets a higher bid and ends the agreement before March 8.
Duff & Phelps was advised by Centerview Partners and got legal counsel from Kirkland & Ellis. The group of buyers' lead adviser was Sandler O'Neill & Partners. Credit Suisse Group, Barclays and RBC Capital Markets also advised and provided financing. Wachtell Lipton Rosen & Katz was legal counsel.