Mark Melchiorre joined UBS Global Asset Managements single-strategy hedge fund unit, UBS OConnor, as managing director and head of credit strategies. The position is new, said Kris Kagel, a UBS spokesman. We believe the market opportunity for his credit-trading skill set is tremendous. With the current downdraft in credit markets and Marks leadership, we feel it is a good time to build the business, Joseph Scoby, managing director and global head of UBS alternatives and quantitative investments group, said in a news release. Mr. Melchiorre was a member of the high-yield credit-trading group at Credit Suisse. Suzanne Fleming, a Credit Suisse spokeswoman, did not respond to a request for further information.