Hyperion Capital Management recently added a professional to help evaluate its investment in sub-prime mortgage assets. Benny Katzburg, previously an associate director in the sub-prime mortgage ratings group at Fitch Ratings in New York, started at Hyperion last month. He reports to Michelle Russell-Dowe, asset-backed portfolio manager. She said the hire represents an addition to what is now a three-strong team analyzing potential investments in asset-backed securities.