UPDATE 3-Fund manager Ramius to buy investment bank Cowen

* New co to retain Cowen name, continue to trade on Nasdaq

* Ramius, another investor to own 71.24 pct of new co

* Ramius' founder Peter Cohen to become CEO

* Cowen shares up as much as 45 pct (Recasts, adds NEW YORK dateline, details, updates shares)

By Paritosh Bansal and Supantha Mukherjee

NEW YORK/BANGALORE, June 4 (Reuters) - Hedge fund manager Ramius LLC agreed to buy investment bank Cowen Group Inc COWN.O in an all-stock deal to create a company that could acquire other funds and lure talent displaced by the financial crisis.

The combined company, which will retain the Cowen name but have Ramius founder and Wall Street legend Peter Cohen as chief executive, is being created three months after an aborted takeover attempt by rival Rodman & Renshaw Capital Group Inc (RODM.O).

Cowen, whose shares soared 36 percent, is a venerable Wall Street name that has lost money since it was spun off by French bank Societe Generale (SOGN.PA) in 2006. In December, it had rejected Rodman's offer to buy the company for $7 a share, or nearly $100 million.

The new firm will have investable assets and cash of about $380 million and minimal debt. Ramius, which is privately held, would also now have stock that can be used for further acquisitions.