Weekly AI Digest: OpenAI’s $500B Valuation, Comet Goes Free & Sora 2 Launch

Week 40, 2025

This week’s AI stories reflect the industry’s growing split between power consolidation and platform experimentation. OpenAI’s secondary share sale officially makes it the world’s most valuable private company, valued at half a trillion dollars. Meanwhile, Perplexity challenges Google’s dominance by making its Comet browser free for everyone, pushing the idea of an “AI-native internet.” And OpenAI doubled down on creative AI with Sora 2, its upgraded generative video model, paired with new commitments to “responsible deployment.”

Let’s jump in!

OpenAI Becomes the World’s Most Valuable Private Company

OpenAI has reached a $500 billion valuation after a private secondary share sale, surpassing SpaceX and making it the most valuable startup on the planet.
The deal allowed employees and early investors to sell $6.6 billion worth of shares to institutional backers.

This was not a fundraising round but a liquidity event, meaning OpenAI didn’t raise new capital, instead, employees gained partial cash-out opportunities. Still, the valuation reflects growing investor confidence that OpenAI’s dominance in both infrastructure (GPT models, Azure integration) and products (ChatGPT, Codex, Sora) will translate into sustained revenue growth.

Read more on TechCrunch

Perplexity’s Comet Browser Goes Free (and Smarter)

Perplexity AI made a bold move this week by making its Comet AI browser free for all users. Previously part of its $200/month “Max” tier, Comet now offers a free version with daily limits, while paid subscribers get full access and a new feature called the Background Assistant.

Comet combines browsing, search, and reasoning into a single interface. Users can ask questions directly in the side panel and get contextualized answers without switching tabs.

By removing the paywall, Perplexity is signaling an aggressive user-acquisition phase, betting that distribution, not monetization, is the bottleneck for AI browsers. Whether consumers embrace a world where “every tab talks back” will define whether Comet becomes a true platform or just another AI experiment.

Read more on TechCrunch

OpenAI Launches Sora 2 — With a Focus on Responsible Use

OpenAI introduced Sora 2, the next generation of its video-generation model. The update improves frame realism, temporal coherence, allowing creators to move from script to finished animation inside the same ecosystem.

Alongside the technical release, OpenAI published two major documents:

• Introducing Sora 2 — detailing the model’s new capabilities and performance gains.
• Launching Sora Responsibly — outlining safety practices, content labeling, and watermarking systems to prevent misuse.

The tone of the announcement was deliberate. OpenAI is positioning itself as a responsible first mover in generative video, aiming to preempt regulatory backlash and maintain credibility ahead of future launches (rumored to include multimodal GPT-5 updates later this year).

Where Startup Dollars Really Go: a16z AI Application Spending Report

Andreessen Horowitz (a16z) published a detailed AI Application Spending Report, analyzing where early-stage AI startups allocate their budgets. The key takeaway: more than 70% of spend goes to inference and hosting, while only ~15% is devoted to core model development.

This indicates most startups are still “thin wrappers” — applications dependent on external LLM APIs (OpenAI, Anthropic, Mistral) rather than proprietary tech. a16z predicts that over time, verticalized “AI-native apps” will replace these wrappers through deeper integration and specialized data pipelines.

For founders, the message is simple: value will accrue to those who own context and data, not just the interface.

Read more on a16z

Periodic Labs: Top AI Researchers Leave Big Tech to Rebuild Science

A quiet but significant story from The New York Times: more than 20 AI researchers have left OpenAI, DeepMind, and Meta to join Periodic Labs, a new San Francisco startup founded by Liam Fedus (co-creator of ChatGPT) and Ekin Dogus Cubuk (former DeepMind scientist).

Backed by $300 million in funding from a16z and others, Periodic Labs aims to create AI systems that accelerate scientific discovery across physics, chemistry, and materials science. Unlike LLM-driven chatbots, their approach blends machine learning with real-world robotics — running thousands of physical experiments, learning from results, and iterating toward new materials and compounds.

Read more on The New York Times

Final Thoughts

Week 40 paints a picture of an AI economy that’s maturing, and concentrating. OpenAI’s valuation milestone shows capital markets are treating frontier models like utilities. Perplexity’s Comet reflects how distribution and interface design are becoming the new competitive fronts. Sora 2 pushes AI further into creative media, while a16z’s data confirms that most of the ecosystem still runs on borrowed infrastructure.

As always, stay curious,
– Ivo