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AI Daily Brief — 31 March 2025

The biggest funding round in private tech history closes, generative video grows up, and ChatGPT breaks its own launch record. OpenAI took $40B at $300B and tied the second tranche to its for-profit conversion clearing by year-end. Runway shipped Gen-4 with cross-shot character consistency. Sam Altman publicly noted ChatGPT had just added a million users in a single hour.

Top stories

  • OpenAI closes $40B SoftBank-led round at $300B post-money. SoftBank committed $30B, with Microsoft, Coatue, Altimeter and Thrive filling the $10B sleeve — nearly double OpenAI’s prior $157B mark. SoftBank’s commitment can drop to $20B if OpenAI fails to complete its for-profit restructuring by Dec 31, 2025 — a condition requiring Microsoft and California AG sign-off and shadowed by Musk’s pending litigation. via CNBC
  • OpenAI publishes ‘New funding to build towards AGI’ note. Same-day blog framing the financing as fuel for AGI infrastructure and Stargate build-out, with the company now serving 500M weekly active ChatGPT users. via OpenAI
  • Runway launches Gen-4 with reference-image character consistency. A video model that anchors characters, objects and environments to user-supplied reference images so identities stay consistent across separate generations without fine-tuning. Clips are 5 or 10 seconds at 720p (4K upscale on paid tiers), 24 fps. Reviewers framed character consistency as the first genuine leap past Gen-3 Alpha. via TechCrunch
  • ChatGPT adds 1 million users in a single hour. Sam Altman said ChatGPT added one million new users in the previous hour — faster than the original November 2022 ChatGPT launch. The Ghibli-fueled GPT-4o image generator was the driver. Weekly active users crossed 150M for the first time. via Cybernews
  • Microsoft data-center lease pullback story crystallizes. Reporting detailed Microsoft cancelling leases totaling several hundred MW with at least two private operators and passing on converting statements-of-qualification into leases — including a reported $12B walk-away from extra CoreWeave capacity. Google and Meta named as snapping up some of the abandoned capacity. A sobriety check on the AI build-out, not a retreat — Microsoft’s $80B FY25 AI capex pledge stands.
  • Bloomberg: xAI/X stock-swap hands X investors an unexpected win. Quantified how X equity holders — bruised since the 2022 take-private — were marked back to near their original cost via Friday’s xAI Holdings deal at $113B combined valuation. via Bloomberg

Who shipped

OpenAI ran the funding day; Runway shipped Gen-4. Anthropic signed an MOU with the Australian federal government on AI safety research, extending its pattern of government partnerships beyond US/UK AISIs. Cisco brought its Webex AI Agent to general availability.

Open-source pulse

No major open-weights drop dated Mar 31. Runway Gen-4 is closed-weights; the differentiator is the reference-conditioning architecture rather than the weights themselves.

Money, infra & hardware

OpenAI’s $40B / $300B close is the largest private financing on record. Runway’s Gen-4 sets a new commercial bar for video character consistency. Microsoft’s lease pullback reframes how aggressively hyperscalers are willing to lock in capacity at current pricing.

Quiet corners

No major frontier model release from Google, Meta or DeepSeek. No notable arxiv landmark dated Mar 31.

By the numbers

  • $40B / $300B / $30B — OpenAI round / post-money / SoftBank commit
  • $20B — minimum SoftBank commit if for-profit conversion misses Dec 31, 2025 deadline
  • 1M users / 1 hour — ChatGPT growth peak; 500M WAU baseline
  • 5/10 sec, 720p, 24 fps — Runway Gen-4 clip parameters
  • $12B — Microsoft’s reported walk-away from extra CoreWeave capacity
  • Most-mentioned company: OpenAI

Compiled by AI Feed’s editor from verified web sources for 31 March 2025.