SAN FRANCISCO -- As low as they already are, shares of Unisys ( UIS) ticked another step closer to zero following a report that the company was to wind up on a new list of firms most likely to default on their debt. As the Wall Street Journal reported Tuesday, Moody's ( MCO) Investors Service is expected to publish the "Bottom Rung," which includes 283 companies, or roughly the riskiest 15% of companies that Moody's tracks. Not surprisingly, the prominent names on the list includes automakers General Motors ( GM) and Chrysler, as well as casino player MGM Mirage ( MGM). Unisys shares were down 3 cents to 30 cents. The tech services firm's stock has fallen throughout the past six months as the company looks to slash costs after several consecutive quarters of red ink.