Microsoft Corp., the world’s largest software maker, plans to sell $3.75 billion of debt in its first bond offering, taking advantage of its top credit ratings to help fund a share buyback and technology investments.

The sale will be split among $2 billion of 5-year notes, $1 billion of 10-year debt, and $750 million of 30-year bonds, according to a person familiar with the offering who declined to be identified because terms aren’t set.

Microsoft, whose shares have declined 34 percent in the past year, is seizing on a credit-market rally to help fund a $40 billion stock repurchase program. The company, which for years resisted shareholder demands to add debt, is also investing in data centers to compete against Google Inc. in Internet search.