Sprint Corp. is paying above-market interest rates on new notes to become the leading issuer of U.S. junk bonds this year as it seeks to fund an expansion of the country's third-largest wireless network.

Sprint raised $2.5 billion Monday with securities due in June 2024 paying a coupon of 7.125 percent, 66 basis points more than the average yield for similar-maturity debt in the B credit rating tier, according to data compiled by Bloomberg. The sale adds to Sprint's more than $12 billion of issuance in the past 24 months to lead speculative-grade borrowers during two years of record annual offerings of at least $350 billion.

Enticing bond investors with higher-than-average coupons may help the Overland Park, Kansas-based company finance capital expenditures that are growing at a faster pace than AT&T Inc. and Verizon Communications Inc. Monday's sale followed a $6.5 billion offering in September that ranked as the biggest high-yield issue since 2008.