Amazon.com Inc. sold bonds to refinance debt and buy back stock, as cheap borrowing costs proved too tempting to resist, even for a company with tens of billions of dollars in cash.

The online retail giant issued $18.5 billion of debt in eight parts. The longest portion, a 40-year security, yields 95 basis points (bps) over Treasuries, after initial price talk at around 115 bps, according to people with knowledge of the matter who asked not to be identified because the details are private.

Companies have been taking advantage of wide-open bond markets and spreads at three-year lows to score cheap borrowing, even if they don't need it. With the economy rebounding from the pandemic, U.S. investment-grade firms are increasingly tempted to spend their cash cushions on acquisitions and dividend hikes, or borrow even more.