S&P Global Ratings assigned an "AA-" long-term rating to Cambridge, Mass.-based the Broad Institute's series 2016 bonds.
"We believe the Broad's overall financial and enterprise profile is sound, with a strong base of grant awards from government and nongovernment sources and robust philanthropic support," said S&P analyst Charlene Butterfield.
The outlook is stable, reflecting S&P's view of the Broad Institute's ability to continue to generate positive operations.
S&P also affirmed the "AA-" long-term rating on the Broad Institute's series 2011A and 2011B bonds.