Anthropic and OpenAI both filed confidential S-1 registration statements with the SEC in June 2026, setting the stage for what could be the most consequential tech IPOs since, well, ever.
Behind the scenes, the financial machinery is even more interesting than the filings themselves. Major private credit firms and Wall Street banks are assembling enormous debt structures around both companies, with the explicit goal of securing investment-grade credit ratings that would make these AI ventures look less like moonshots and more like blue-chip infrastructure plays.
The numbers behind the curtain
Anthropic, the maker of the Claude AI models, filed its confidential S-1 on June 1. OpenAI followed a week later on June 8. Both companies are eyeing valuations north of $850 billion, with the upper end stretching past $1 trillion.
Anthropic closed a staggering $65 billion Series H funding round in late May 2026, which pegged its post-money valuation at $965 billion.
Apollo Global Management and Blackstone have finalized a structured notes package worth approximately $35 to $36 billion, designed specifically to finance AI chip procurement for Anthropic. Those notes received mid-investment-grade ratings, with Broadcom providing backing.
A consortium of banks including Morgan Stanley, Goldman Sachs, JPMorgan, and Citigroup is putting together a $15 billion pre-IPO revolving credit facility for Anthropic.
Why credit ratings matter here
Most institutional investors, including pension funds, insurance companies, and sovereign wealth funds, operate under mandates that restrict them to investment-grade securities. By securing those ratings on the structured notes and credit facilities surrounding Anthropic, Apollo and Blackstone are essentially building a bridge between Silicon Valley risk appetite and Main Street pension money.
A crowded runway
Anthropic and OpenAI aren’t filing into a vacuum. The 2026 IPO window is shaping up to be one of the busiest in years, with SpaceX also reportedly in the mix for a potential public listing. All three companies are competing for the same finite pool of institutional investor capital.
Anthropic appears to be positioning itself for a Nasdaq listing potentially as early as October 2026. The company has essentially compressed a decade of typical corporate finance evolution into about five years, going from founding to near-trillion-dollar valuation with institutional-grade credit infrastructure in place.
The sheer scale of capital flowing into AI infrastructure through these credit structures, roughly $50 billion in debt financing for Anthropic alone between the structured notes and revolving facility, is beginning to reshape credit markets. Asset managers who previously had no exposure to AI are now holding investment-grade notes backed by chip leases.