A deep-dive of the 37 most valuable private companies

Including Waymo (600x), Perplexity (90x), OpenAI (70x)

👋 Hi, it’s Palle Broe and welcome to Rule of Thumb, my weekly newsletter exploring the startup and tech world providing tangible advice and insights from the worlds best operators and startups

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$1.5 trillion—that’s the total value of the 37 most valuable private startups. Unlike just 2–3 years ago, the list is now filled with AI-native startups, with 2 of the top 3 most valuable private companies being AI firms (OpenAI, xAI).

AI is clearly rewriting many of the traditional startup rules—especially when it comes to valuations and revenue multiples. Much of the current value is tied to sky-high expectations of future revenue, and when combined with intense competition among investors, this has led to revenue multiples reaching as high as 600x (compared to an average public SaaS multiple of 7x).

Key takeaways

1. 𝐀𝐈 𝐢𝐬 𝐤𝐢𝐧𝐠: Companies like Waymo (600x), Perplexity (90x), OpenAI (70x) and Anthropic (44x) are commanding sky-high multiples. Investors are betting big on the future of artificial intelligence — even when current revenue is modest.

2. 𝐍𝐨𝐭 𝐚𝐥𝐥 𝐫𝐞𝐯𝐞𝐧𝐮𝐞 𝐢𝐬 𝐯𝐚𝐥𝐮𝐞𝐝 𝐞𝐪𝐮𝐚𝐥𝐥𝐲: Stripe has $5B in revenue but a 18x multiple. Fanatics makes over $8B but trades at just 4x. Meanwhile, Waymo — with only $75M in revenue — is valued at a stunning 600x.

3. 𝐏𝐫𝐢𝐯𝐚𝐭𝐞 𝐯𝐬 𝐏𝐮𝐛𝐥𝐢𝐜 𝐛𝐞𝐧𝐜𝐡𝐦𝐚𝐫𝐤𝐬: More than 90% of the companies on the list have a higher revenue multiple than the average 7x we are seeing for SaaS companies in the current market. Valuations in the private market are likely still inflated vs what they would trade for.

Methodology

• Sources: Public available sources, Harmonic, and Crunchbase.

• The top 37 unicorns selected in this deep-dive were chosen by the author. Focused on the application layer and unicorns (although a few fall just short of this definition).

• Data is as of May 25, 2025 (or otherwise, as stated on the graphs).

• Valuation and revenue data taken from various online public sources. Treat the numbers below as directional, not as exact figures.

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Most valuable Startups

A few observations from the list:

1. Companies staying private longer: More companies are staying private longer — raising bigger rounds, growing massive user bases, and delaying IPOs. As a result, the private market has become home to companies once considered “public-scale.”. Companies like SpaceX, OpenAI, xAI and Stripe are all close to or above $100B in valuation.

2. AI domination: If you had looked at this list but 5 years ago none of the large AI native companies would be here. Now they are dominating the list and this trend is likely to only increase over the next few years.

3. US leading the pack: Unsurprisingly the US is leading the list with 32 out of 37 companies having been founded in the US.

Highest Revenue Multiples

The chart below shows how some of the world’s most valuable private companies stack up on one simple metric: Revenue multiple. While revenue tells us how much money a company is currently making, the multiple tells us how much investors believe in its future.

• AI is king: Companies like Waymo (600x), OpenAI (70x), Anthropic (44x), and Perplexity (90x) are commanding sky-high multiples. Investors are betting big on the future of artificial intelligence — even when current revenue is modest.

• Not all revenue is valued equally: Stripe has $5B in revenue but a 18x multiple. Fanatics makes over $8B but trades at just 4x. Meanwhile, Waymo — with only $75M in revenue — is valued at a stunning 600x.

• Private vs Public benchmarks: More than 90% of the companies on the list have a higher revenue multiple than the average 7x we are seeing for SaaS companies in the current market. Valuations in the private market are likely still inflated vs what they would trade for.

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