Open AI Cap Table Executive Summary – 11/11/2025

1. Microsoft – 27%
2. OpenAI Board – 26%
3. SoftBank + Series E Investors – 13%
4. Series D Investors – 4%
5. OpenAI’s Series A round (other than Microsoft) – 1% supposedly
6. Employees – 25% supposedly
7. YCombinator – Perhaps 7%

Please Note: This is based on publicly available information and might be inaccurate.

Please Note: This is subject to change based on further fund raising by OpenAI and on sales by current investors and current employees.

Open AI Investments & Funding Rounds

1. Seed in 2016 -> $120K from YCombinator in 2016. Unconfirmed whether this was done (as OpenAI got a $1 billion grant in 2015). Unconfirmed whether or not YCombinator got 7% Equity in OpenAI
2. Series A on July 22nd, 2019 -> $1 Billion at Unknown Valuation from Microsoft and Matthew Brown Companies
3. Series B on Jan 23rd, 2023 -> $10 Billion at $27 Billion Valuation from Microsoft and others. 32.5% Equity to Microsoft
   • Please Note: As of 11/11/2025, Microsoft has 27% Equity in OpenAI and the OpenAI Non Profit Board has 26% Equity in OpenAI
4. Series C on Apr 28th, 2023 -> $300 Million at Unknown Valuation from Multiple Investors
5. Series D on Oct 2nd, 2024 -> $6.6 Billion raised at $157 Billion Valuation. 4% Equity for $6.6 Billion
6. Series E in 2025 -> $40 Billion raised at $300 Billion Valuation from SoftBank and others. 13% Equity for $40 Billion
   • Softbank investment was contingent on OpenAI restructuring as a For Profit (which it has done by 11/11/2025)

You can also check Traxcn for a different take on OpenAI’s funding rounds -> OpenAI – 2025 Funding Rounds & List of Investors – Tracxn (https://tracxn.com/d/companies/openai/__kElhSG7uVGeFk1i71Co9-nwFtmtyMVT7f-YHMn4TFBg/funding-and-investors#funding-rounds).

Open AI Original Founding Details

OpenAI was originally founded as a Non Profit with $1 Billion of Grant Money from Peter Thiel, Elon Musk, Reid Hoffman, Infosys and others.

Open AI Seed Round Details

In 2016 OpenAI participated in YCombinator. The usual funding from YCombinator is $120K for 7% Equity.

It is not clear whether YCombinator took any equity. It is also not clear whether YCombinator invested any money in Open AI.

Open AI Series A Details

A master stroke by Microsoft where Microsoft invested $1 Billion in OpenAI on July 22nd, 2019 and got its foot in the door.

Open AI Series B Details

Microsoft invested $10 Billion at a $27 Billion valuation on Jan 23rd, 2023. This got Microsoft 32.5% equity.

Even now, after further rounds, Microsoft still has 27% equity in OpenAI.

Open AI Series C Details

This was a relatively small investment of $300 Million at an Unknown Valuation on April 28th, 2023.

As it is close after Microsoft’s $10 billion investment it would not be a surprise if the valuation was $27 or $30 Billion.

The investors included Tiger Global, Andreesen Horowitz, Founders Fund, Flat Capital etc. It almost seems like a ‘let the big players in Silicon Valley get a small piece’ round.

Open AI Series D Details

This was a $6.6 Billion investment at a $157 Billion valuation on Oct 2nd, 2024.

Investors were led by Thrive Capital and included Khosla Ventures, Microsoft, etc.

Debt Funding between Series D and Series E in October 2024

OpenAI took on $4 billion of conventional debt on Oct 7th, 2024 from Wells Fargo, UBS, HSBC, Goldman Sachs, etc. This was just a debt round and not VC funding.

Open AI Series E Details

This was SoftBank investing $40 Billion at a $300 Billion valuation on Mar 31st, 2025.

There were also other investors including Microsoft, Coatue, and Thrive Capital.