Microsoft Corp. raised $19.75 billion Monday in the third-largest U.S. corporate bond sale of the year to help finance its planned purchase of LinkedIn Corp.

Investors put in more than $50 billion of orders for the deal in the software maker's biggest ever sale. The strong demand helped Microsoft to borrow at lower rates than it paid for the $13 billion of bonds it raised in October. It also saved about $40 million in annual interest payments compared with what it was offering to pay initially, according to people familiar with the matter.

Investors have been clamoring for U.S. corporate debt in recent months. Yields are turning negative on a growing number of bonds globally as central banks in Japan and Europe ramp up stimulus packages, spurring money managers to seek higher returns in the U.S.