The fund invests mainly in bonds that are below investment grade in quality with a focus on companies or issuers that Putnam Management, the fund"s investment manager, believes meet relevant environmental, social or governance criteria on a sector-specific basis ("ESG criteria"). The fund invests mainly in bonds that also have one or more of the following characteristics: (1) are obligations of U.S. companies or issuers and (2) have intermediate- to long-term maturities (three years or longer).