Summary. OpenAI’s disclosed financing path runs from a 2019 capped-profit limited partnership that raised an initial round of over $100 million, plus a $1 billion Microsoft investment that year, to a March 2026 close of $122 billion in committed capital at an $852 billion post-money valuation. The late stage is dominated by strategic capital bundled with cloud and chip supply—Microsoft first, then SoftBank at scale, then Amazon and NVIDIA as anchors—while the company moved from capped-profit terms to a public benefit corporation so it could raise conventional equity at frontier-AI size. This teardown uses only what OpenAI and named investor primaries have published.
Why OpenAI: the company and SoftBank/Amazon disclose amount and (for the priced late rounds) valuation with enough precision to check step-ups and new-money share. Early Microsoft extensions and the 2021 Microsoft investment are named without amounts, so those cells stay “Not disclosed.” Runner-ups for future teardowns: Harvey (legal AI) and Glean (enterprise search).
Sourcing rule for this piece: every number below comes from an OpenAI announcement or a SoftBank Group, Amazon, or other named-investor primary. Where OpenAI did not disclose amount, valuation, or lead, we write “Not disclosed” and do not fill the gap from press reports.
The timeline
Date | Round | Amount | Post-money (disclosed) | Lead(s) | Other notable investors / terms | Source |
|---|---|---|---|---|---|---|
Mar 11, 2019 | OpenAI LP (first LP round) | Over $100M (company restatement, Dec 2024); LP post itself does not state the dollar amount | Not disclosed | Not disclosed | Reid Hoffman’s charitable foundation; Khosla Ventures; first-round investor returns capped at 100x | |
Jul 22, 2019 | Strategic | $1B | Not disclosed | Microsoft | Exclusive cloud on Azure; preferred commercialization partner for pre-AGI tech | |
2021 | Strategic | Not disclosed | Not disclosed | Microsoft | Named only as a prior investment in the Jan 2023 extension post | |
Jan 23, 2023 | Strategic extension | Multi-year, multi-billion (exact amount not disclosed) | Not disclosed | Microsoft | Azure remains exclusive cloud for OpenAI workloads; builds on 2019 and 2021 investments | |
Oct 2, 2024 | Equity raise | $6.6B | $157B | Not disclosed | SoftBank later disclosed $2.2B via SoftBank Vision Fund 2 since Sep 2024; OpenAI did not name SoftBank (or any other firm) as lead of this round | |
Oct 3, 2024 | Revolving credit | $4B facility, undrawn at close | n/a | Bank syndicate (JPMorgan Chase, Citi, Goldman Sachs, Morgan Stanley, Santander, Wells Fargo, SMBC, UBS, HSBC) | Combined with the $6.6B equity raise, OpenAI said liquidity access was over $10B | |
Mar 31, 2025 (announced; funded Apr–Dec 2025) | Equity raise | $40B (OpenAI announcement); SoftBank reports final funded aggregate of $41.0B including co-investors | $300B | SoftBank Group (OpenAI: partnership with SoftBank) | SoftBank agreement: up to $40B with up to $10B syndication; SoftBank funded $7.5B + $22.5B = $30B via SVF2; co-investors $11B; pre-money $260B in SoftBank filing; convertible interest rights → preferred with 1x liquidation preference after recap | |
Feb 27, 2026 | New investment announced (round in progress) | $110B new investment at $730B pre-money | Not stated as a closed post-money on this date | SoftBank $30B; NVIDIA $30B; Amazon $50B named | Additional financial investors expected; Amazon commercial package parallel (see below); SoftBank: preferred shares in OpenAI Group PBC in three $10B tranches at $730B pre | |
Mar 31, 2026 | Close of latest round | $122B committed capital | $852B | SoftBank co-led with a16z, D. E. Shaw Ventures, MGX, TPG, and accounts advised by T. Rowe Price Associates | Anchored by Amazon, NVIDIA, SoftBank; Microsoft continued; bank-channel individuals raised over $3B; revolver expanded to ~$4.7B, undrawn at close |
OpenAI has not published a full early-stage series letter (A/B/C…) schedule the way Anthropic has. We therefore list rounds as the company labeled them—LP formation, Microsoft strategics, named equity raises—and leave blanks where amount or lead is absent from primary sources.
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