Ceridian Corp, surviving entity of the Control Data Corp Big Bang, has found favor with Moody’s Investors Service Inc, which has upgraded Ceridian’s 5.5% convertible exchangeable preferred stock rating to ba3 from b1 and assigned a first time rating of Ba1 to the company’s $325m unsecured revolving credit facility, which is due to run out in November 1998. The outlook on the rating is positive, and reflects the continued shift toward higher margin service revenues; stable operating margins at a time of investment and integration; strong cash flows, reduced debt; and improved interest and preferred coverage. The positive outlook anticipates further margin improvement from the company, particularly as it moves to a centralized and updated computer system for its personnel products, it says and likes the high recurring revenues and strong market position of its businesses.