Companies borrowing to complete deals and prop up their stockprices are helping to keep U.S. investment-grade debt sales atabout a record pace, defying predictions of a slowdown.

Apple Inc. and Leuven, Belgium-based Anheuser-Busch InBev NVhave led $476.6 billion of offerings this year, almost matching the$477.4 billion sold during the same period in 2013, anunprecedented year for U.S. issuance, according to data compiled byBloomberg. Apple's $12 billion deal to fund shareholder rewards andAB InBev's $5.25 billion sale in January to finance its purchase ofSouth Korea's Oriental Brewery Co. are spurring the second-busiestperiod ever for debt sales used to fund mergers, acquisitions,dividends and share buybacks.

Companies are taking advantage of an unexpected reprieve fromrising borrowing costs after a first-quarter economic slowdown andtepid inflation boosted demand for fixed-income assets. Whileanalysts ended 2013 predicting high-grade sales would lose steamthis year amid rising interest rates, borrowing benchmarks haveinstead declined to an 11-month low.