Anthropic and OpenAI filed confidential S-1 registration statements with the SEC in June 2026, setting up potential IPOs that could rank among the most significant technology listings. Both companies are targeting valuations above $850 billion, with the upper range exceeding $1 trillion. Anthropic, maker of the Claude AI models, filed on June 1, followed by OpenAI on June 8. Anthropic raised a $65 billion Series H round in late May 2026, giving it a post-money valuation of $965 billion. Apollo Global Management and Blackstone finalized approximately $35 billion to $36 billion of structured notes to finance Anthropic's AI-chip procurement, with Broadcom providing backing and the notes receiving mid-investment-grade ratings. Morgan Stanley, Goldman Sachs, JPMorgan and Citigroup are arranging a $15 billion pre-IPO revolving credit facility for Anthropic. The ratings are important because pension funds, insurers and sovereign wealth funds often face mandates limiting them to investment-grade securities. Anthropic and OpenAI are entering a busy 2026 IPO market that may also include SpaceX, competing for a limited pool of institutional capital. Anthropic is positioning for a possible Nasdaq listing as early as October 2026. The financing arrangements amount to roughly $50 billion of debt financing for Anthropic and are bringing investment-grade notes backed by chip leases to asset managers that previously had no AI exposure.