Mark Berg has left Lehman Brothers' high-yield and bank loan group to go to CIBC Capital Markets. Berg is expected to join CIBC's loan desk as an executive director and trader. The trading spot at CIBC has essentially been unfilled since Paco Torrado, a par trader, left the firm last fall, said one buysider. Berg declined to comment. John Burke, a CIBC loan sales official, did not return calls by press time. Officials at Lehman declined to comment and a spokeswoman did not return calls.