Circle published a breakdown of the assets backing its USDC stablecoin in its latest attestation report. According to the report, on May 28 bout 61% of its tokens were backed by cash and money market funds. Yankee certificates of deposit (i.e., issued by non-US banks) comprise a further 13%, short-term U.S. Treasury securities account for 12%, unsecured commercial paper accounts for 9%, and the remaining tokens are backed by unsecured short-term municipal and corporate bonds.
By "short-term" is meant a maximum term to maturity of three years, and the overall portfolio weighted average maturity is limited to 1.5 years. There are also credit rating limits based on S&P scales. The overall portfolio must main an average credit rating must of A or better, commercial paper holdings must be rated A1 on the short-term scale, and for bonds issued by corporations and financial institutions must be rated BBB+ or higher on the long-term scale.
