Global corporate bond issuance reached $2.8 trillion in the first six months of 2026, surpassing the previous record set in 2020 by 11%, according to capital markets data released this week. AI infrastructure companies—chipmakers, hyperscalers, and data-center REITs—accounted for $680 billion of total issuance, roughly a quarter of the market. The concentration is tightest in high-yield: 38% of new sub-investment-grade paper came from data-center operators and their equipment suppliers, up from 9% in 2023.

The surge reflects the capital intensity of the AI buildout. Nvidia suppliers are financing semiconductor fabs with 7-year notes yielding 5.2% to 6.8%. Hyperscalers issued $240 billion in investment-grade debt to fund capacity expansion, with Microsoft and Google each placing $40 billion in tranches ranging from 3 to 30 years. Data-center REITs, meanwhile, tapped high-yield markets for $180 billion, often at spreads above 400 basis points over Treasuries. The pace accelerated in May and June as tariff uncertainty around Taiwan semiconductor imports pushed companies to front-load capex.

The concentration creates path dependency for bond investors. High-yield portfolios now carry 22% average exposure to AI infrastructure, compared to 6% exposure to energy in early 2020. Default correlation is tight: if hyperscaler capex slows or chip demand plateaus, the entire stack—from REIT landlords to equipment lessors—faces simultaneous refinancing pressure. Covenants are thin. 64% of new high-yield AI debt includes covenant-lite structures, and 19% features payment-in-kind toggle options that let issuers defer cash interest if EBITDA targets slip. The market is pricing continued growth, not cyclicality.

Allocators should watch three near-term events. Nvidia reports September quarter results in mid-October, and any guidance cut will reprice the entire AI debt stack within 48 hours. Second, $92 billion in data-center REIT debt matures between Q4 2026 and Q1 2027, requiring refinancing into a market that may no longer assume 20% annual revenue growth. Third, the Fed's December meeting will clarify the terminal rate path; if the committee signals cuts are off the table into 2027, spreads on covenant-lite AI paper will widen 80 to 120 basis points within the month. Meanwhile, emerging-market flows are stabilizing—$3.7 billion returned to EM funds over two weeks—but the capital is rotating into rate-sensitive financials and utilities, not the tech exposure that drove 2025 performance.

By November, the high-yield AI debt pile will either begin its repricing or prove that infrastructure spend is countercyclical to traditional credit. The market has already chosen which it believes.