Cowen Group (NASDAQ:COWN) announced that it has signed a definitive agreement to buy Dahlman Rose. The purchase is an all-stock transaction, although the price was not disclosed.

Cowen made the deal because of the privately held Dahlman Rose's areas of expertise. Cowen quoted its own CEO, Peter Cohen, as saying that "Dahlman Rose's expertise in energy, transportation, metals and mining, chemicals, and agriculture is a strong complement to Cowen core sectors of health care, technology, media, telecommunications, consumer, aerospace and defense/industrials, and REITs."

The transaction is expected to close by the end of March. It is subject to regulatory approval.