Sales of longer-term bonds are accelerating at a record pace in the U.S., with corporate borrowers from Morgan Stanley to FedEx Corp. each selling 30- year debt for the first time in at least a decade.

Issuance of investment-grade bonds maturing in 30 years or more totals $83.6 billion since year-end, already exceeding the annual total in 2010 and 2011, according to data compiled by Bloomberg. Offerings are growing about six times faster than the overall high-grade market.

Corporate treasurers are exploiting record-low borrowing costs as the Federal Reserve says it will hold its target interest rate at between zero and 0.25 percent through at least late 2014. An average yield of 4.57 percent on investment-grade securities maturing in 15 years or more is lower than the rate borrowers paid in 2009 to raise funds due in one to three years.