Commercial mortgage-backed securities are beginning to make a comeback but with a different cast of players. Well-established JPMorgan leads the pack. Some of the major CMBS issuers of the past—such as Wachovia, Bear Stearns, Merrill Lynch and Lehman Brothers--either no longer exist or are now part of other firms, while newcomers, including Ladder Capital and Cantor Fitzgerald, are beginning to emerge.