In a sign of its growing financial maturity and clout, an item in today’s edition of Bloomberg (bloomberg.com) reports that Google (ticker GOOG) has successfully completed its first foray into the bond market with a $3 billion sale to pay back short-term borrowings at relative yields comparable to companies with the highest credit ratings, tapping the corporate bond market as investment-grade borrowing costs tumble to about the lowest since November.

The world’s biggest Internet-search company split the sale evenly between three-, five- and 10-year notes, according to data compiled by Bloomberg. The 1.25 percent, three-year notes yield 33 basis points more than similar-maturity Treasuries, the 2.125 percent, five-year debt pays a 43 basis-point spread, and the 3.625 percent, 10-year securities offer 58 basis points above benchmarks, Bloomberg data show. The debt market priced Google’s debt at the level of AAA rated companies.

Until now, Google has relied on a short-term debt financing program that allowed it to borrow as much as $3 billion by issuing commercial paper, according to the quarterly filing. The debt has a weighted average interest rate of about 0.3 percent and weighted average maturity of about 163 days, it said today in a filing. Commercial paper typically matures within 270 days and is used to finance everyday activities such as payroll and rent.