The public school district that serves Stockton, Calif., which became the biggest U.S. city to enter bankruptcy in June, plans to issue $45 million in debt as soon as next week in its first sale since the municipality sought chapter 9 protection, Bloomberg News reported on Friday. The separately financed Stockton Unified School District, which runs elementary and high schools as well as charter facilities, will issue general-obligation bonds maturing from 2013 to 2027 to refund higher-cost debt, according to data compiled by Bloomberg. It is selling as the yield penalty on its previously issued debt has declined.