SAN FRANCISCO--(BUSINESS WIRE)--Fitch Ratings has assigned an 'AA' rating to the following Fullerton Joint Union High School District, CA (district) obligations: --$21.5 million certificates of participation (COPs) (2015 refinancing project). The COPs are expected to sell via negotiation the week of Aug. 10. Proceeds will be used to refund the district's outstanding 2007 COPs for level debt service savings. In addition, Fitch affirms the following rating: --$22.3 2007 million COPs at 'AA'; --$1