AT&T Inc., the second-largest U.S. wireless carrier, sold $5 billion of bonds to help pay back debt maturing this year.

AT&T sold $1.5 billion of 2.4 percent, five-year notes that yield 148 basis points more than similar-maturity Treasuries, $1.5 billion of 3.875 percent, 10-year debt at a spread of 160 basis points and $2 billion of 5.55 percent, 30-year bonds that pay 185 basis points more than benchmarks, according to data compiled by Bloomberg. Proceeds may also be used for general corporate purposes, said a person familiar with the offering, who declined to be identified because the terms are private.

Corporate bond offerings are showing signs of life, with borrowers from Occidental Petroleum Corp. to San Diego Gas & Electric Co. joining Dallas-based AT&T in tapping the market as yields on investment-grade debt hover at about the lowest on record. Sales rose 37.6 percent last week to $13.6 billion after falling to the lowest since June during the period ended Aug. 5, Bloomberg data show.