A high-stakes showdown pitting California's public employee pension fund against Wall Street bond firms in bankrupt San Bernardino, Calif., could be further complicated by wildly disparate estimates of how much the city owes for its retirees, Reuters reported yesterday. San Bernardino, a city of about 210,000 near Los Angeles that filed for bankruptcy on Aug. 1, has listed the California Public Employees' Retirement System (Calpers) as its largest creditor, with unfunded pension obligations totaling $143.3 million. But Calpers, in response to an inquiry from Reuters, pegged the debt at $319.5 million. Experts say the dramatically different calculations of San Bernardino's debt to Calpers will likely lead to litigation between the two entities, unless the city quickly agrees to the retirement system's figure.