Big Tech’s Costly AI Bet Rides on Hundreds of Billions of Debt

Technology firms with vast funding needs to pay for their AI ambitions are striking blockbuster debt deals at the fastest pace in years, taking advantage of near—insatiable investor appetite to lock in financing for initiatives whose ultimate payoff remains uncertain.

Borrowers are tapping all corners of credit and finding ready buyers. In the US public bond markets alone, tech companies have raised about $157 billion so far this year, up some 70% from what they issued in the same period last year, according to data compiled by Bloomberg.

Oracle has led the way, with nearly $26 billion of publicly traded ...