Emily Bollinger / WGLT Ratings agency Moody’s Investors Service has downgraded Unit 5’s credit rating as part of a new grading system that is affecting hundreds of school districts across the country. School district officials say the change will have no immediate impact. Moody’s dropped Unit 5’s rating from Aa2 to Aa3. Moody’s described the district’s financial position as “solid,” but said the district receives “substantial support for its contributions to an underfunded teacher retirement system.” Marty Hickman, Unit 5’s chief financial officer, noted Illinois lawmakers have discussed a cost shift to make school district’s responsible for paying a greater share of retirement costs.