Graham Capital Management LP purchased the historic Rock Ledge property at 40 Highland Ave. in the Rowayton area of Norwalk, CT, which will undergo renovations over the next year to become a state-of-the-art financial center. The 102,492-square-foot office building and adjoining Rock Ledge mansion were purchased from Hewitt Associates for $17.3 million or approximately $169 per square foot. The complex will be renamed the Rock Ledge Financial Center.