Cowen Group, a US-based diversified financial services firm, has hired Thomas O'Mara as head of equity derivatives and convertibles.

Mr O’Mara will be primarily responsible for expanding the firm’s equity derivative capabilities and building out a presence in the convertible market. He will be based in New York.

Mr O’Mara spent over 14 years at Credit Suisse First Boston where he held a number of senior positions including global head of convertible securities, global head of cash equities and global chief risk officer for the equities division. He also served as a member of the Global Equity Management Committee.

Prior to Credit Suisse First Boston, Mr O’Mara spent five years at Lehman Brothers in the convertible securities group. He has also spent time on the buy side, including managing multi-strategy assets in a hedge fund structure.

Peter Cohen, chairman and CEO of Cowen Group, said: “Tom is a professional with exceptionally broad experience in equity derivatives and convertible trading activities. Tom is ideally suited to work with John O’Donoghue our head of equities to lead the growth of our sales and trading platform, where we continue to expand our product and market reach.”