OpenAI has officially closed its latest funding round with $122 billion in committed capital, marking the largest single funding round in Silicon Valley history and cementing the ChatGPT maker's position as the most valuable private AI company in the world. Announced on March 31, 2026, the round values OpenAI at $852 billion post-money, a staggering figure that surpasses the market capitalizations of most S&P 500 companies. The funding was anchored by major investors including SoftBank, NVIDIA, and Amazon, with continued participation from Microsoft and Andreessen Horowitz (a16z). Notably, the round also includes $3 billion from retail investors through a unique structure that allows public market participation ahead of OpenAI's anticipated IPO. The capital infusion comes as the company prepares for a potential blockbuster public offering targeted for Q4 2026, with analysts speculating about a $1 trillion valuation target. Despite the massive funding and growing monthly revenue, OpenAI remains unprofitable, raising questions about the sustainability of the AI investment boom.

On December 26, 2025, SoftBank Group officially completed its promised $22.5 billion additional investment in OpenAI, fulfilling a March commitment for up to $40 billion total (including co-investors). This massive cash infusion — routed through Vision Fund 2 — elevates SoftBank's stake to approximately 11%, making it OpenAI's second-largest investor behind Microsoft. Amid soaring AI infrastructure costs and OpenAI's push toward AGI, this deal underscores Son's aggressive pivot, achieved through asset sales, loans against Arm shares, and ruthless portfolio pruning.