Fitch Ratings yesterday downgraded more than $252 million of Stockton Public Finance Authority debt after the cash-strapped city voted to allow the city manager to file for chapter 9 protection if necessary, Reuters reported yesterday. Stockton, located about 85 miles east of San Francisco in California's Central Valley, is in confidential talks with its creditors to obtain concessions to help close a $26 million budget gap before the July 1 start of its next fiscal year. Stockton has seen its credit rating slashed since its leaders said in February they would pursue a financial restructuring plan that includes defaulting on some debt payments and seeking mediation with creditors.