Morgan Stanley CEO John Mack will have a low-key retirement party when he steps down from his post at the end of the year. Mindful of the public scrutiny of giant Wall Street banks, Mack, who announced his retire ment in September, will have a modest affair at the Marriott Marquis. “Morgan Stanley em ployees who possess talents other than making money are creating videos to be played at the party,” says an insider. Mack will stay on as chairman of the board.