A gauge of U.S. company credit risk declined as Verizon Communications Inc. completed a record corporate-bond offering.

The Markit CDX North American Investment Grade Index, a credit-default swaps benchmark that investors use to hedge against losses or to speculate on creditworthiness, fell 1.8 basis points to a mid-price of 76.2 basis points as of 4:17 p.m. in New York, according to prices compiled by Bloomberg. The measure typically falls as investor confidence improves and climbs as it deteriorates.

Investors watched the second-largest U.S. phone carrier's $49 billion, eight-part bond sale today to see how the market would react to the issuance, according to Marc Pinto, head of corporate bond strategy at Susquehanna International Group LLP in New York. After Verizon's offering, which was more than double Apple Inc.'s $17 billion transaction in April, the company's swaps declined to the lowest level in a week.