US convertible bond sales hit record high as AI spending devours capital markets

The US convertible bond market just posted a number that would have seemed absurd three years ago. Companies listed in the US have raised $131 billion in convertible debt year-to-date through early September 2026, according to Bloomberg data, blowing past the previous annual record set just two years prior. The culprit, or hero depending on your portfolio, is artificial intelligence. Roughly half of the convertible bonds issued this year are tied to AI initiatives, as companies race to build the data centers, buy the chips, and deploy the infrastructure needed to stay relevant in a market that punishes anyone who falls behind. The deals driving the boom August alone accounted for $25 billion in convertible bond issuance, a staggering single-month haul that underscores how urgent the capital needs have become. The roster of borrowers reads like an AI supply chain directory. CoreWeave tapped the market for $4 billion, Oracle raised $5 billion, ON Semiconductor issued $1.3 billion in zero-coupon convertibles, and Ciena Corp followed with a $2.9 billion zero-coupon deal of its own. Zero-coupon convertibles, bonds that pay no interest at all, are on track for a record year globally. Acc...