A group including publicly traded private equity powerhouse Carlyle Group (NASDAQ:CG) has agreed to buy the Duff & Phelps (UNKNOWN:DUF.DL) investment bank. The consortium that includes Carlyle, Stone Point Capital, Pictet & Cie, and Edmond de Rothschild Group will pay $15.55 per share in cash to acquire Duff for a total transaction value of approximately $665.5 million.

The exact proportions of the buyout were not specified, but in a statement,  Duff &  Phelps said none of the four buyers would be acquiring more than 35% of Duff's shares individually.

This transaction announced on Sunday is expected to close in the first half of 2013. But in the meantime, the putative buyer have granted Duff a "go-shop" window allowing it to seek out competing offers from now through Feb. 8. In the event Duff finds an offer superior to that of Carlyle and its partners, which Carlyle and its partners do not match or beat and which Duff chooses to go with, it will be required to pay today's bidders a $6.65 million break-up fee.

Meanwhile, Duff clarified that it will continue paying dividends to its shareholders from now until the transaction closes.

Shares of Duff & Phelps opened 19.1% higher Monday, and as of this writing are trading slightly above the offer price at $15.57. The offer price of $15.55 per share is a 19.2% premium to the closing price of Duff & Phelps shares on Friday and 27.3% over the company’s volume-weighted average share price during the 30 days ended Dec. 28, according to the company.



Fool contributor Rich Smith has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.