Rain AI
Category: AI Infrastructure
Developing energy-efficient neuromorphic chips designed to mimic the human brain to accelerate AI workloads. Rain AI was founded in 2017. The company is led by William Passo. Based in San Francisco, CA, USA. Team size: 43 employees (2024). Total funding raised: $67 million total ($5M Seed + $25M Series A + $8.1M Series A extensions + $3M Bridge). Latest round: Bridge Loan ($3M, May 2025) - Series B ($150M) failed in 2024. Key investors include Sam Altman (personal investment), Prosperity7 Ventures, FoundersX Ventures.
- Founded
- 2017
- Headquarters
- San Francisco, CA, USA
- Team size
- 43 employees (2024)
- Total funding
- $67 million total ($5M Seed + $25M Series A + $8.1M Series A extensions + $3M Bridge)
Value proposition
Offers a novel neuromorphic, compute-in-memory approach to drastically reduce energy consumption and cost of AI model deployment.
Products and solutions
Neuromorphic Processing Unit (NPU), Digital in-memory compute chips
Unique value
Incorporates brain-inspired neuromorphic architecture with analog compute and in-memory processing using memristor technology to act as artificial synapses.
Target customer
AI-focused enterprises, large-scale AI model developers, and organizations seeking energy-efficient, high-performance AI hardware.
Industries served
Artificial Intelligence, Vision systems, Speech recognition, Natural Language Processing, Recommendation systems
Technology advantage
Potential for significantly faster and more energy-efficient AI computations compared to traditional digital solutions, lowering operating costs.
How they differentiate
Focus on neuromorphic, analog, and compute-in-memory designs that offer superior energy efficiency and cost savings for AI workloads compared to conventional digital chips.
Main competitors
SambaNova Systems, Groq, Cerebras Systems, Nvidia
Key partnerships
OpenAI (letter of intent in 2019 for $51 million in chip purchases)
Notable customers
OpenAI (via a letter of intent)
Major milestones
[ "2017: Founded by Jack Kendall, Gordon Wilson, Juan Claudio Nino", "2018: Raised $5M Seed from Sam Altman and Prosperity 7", "2019: OpenAI Letter of Intent for $51M chip purchases (never executed)", "October 2022: Raised $25M Series A led by Prosperity 7 Ventures", "2023: William Passo (COO) promoted to CEO, Gordon Wilson to Executive Advisor", "2023: Hired Jean-Didier Allegrucci (ex-Apple) as Head of Hardware Engineering", "2024: Multiple Series A extensions ($8.1M each) to extend runway", "2024: $150M Series B round FAILED to materialize", "June 2024: Secured $3M bridge loan to sustain operations", "2024: Forced divestment from Prosperity7 due to US national security concerns", "May 2025: Additional $3M bridge loan secured", "2025: Exploring acquisition - in talks with OpenAI, Nvidia, Microsoft" ]
Growth metrics
Rapidly depleting cash reserves as of 2024-2025. Secured multiple bridge loans ($3M in 2024, $3M in May 2025) to sustain operations. 43 employees (2024). In active acquisition talks with major players (OpenAI, Nvidia, Microsoft). Prototype demonstrated 8× energy reduction vs GPU.
Market positioning
Emerging startup with a unique technology proposition, though currently facing financial challenges and strategic restructuring.
Geographic focus
Primarily US-based with a focus on Silicon Valley innovation ecosystem.
Patents and IP
Patent filings pending for their novel compute-in-memory technology.
About William Passo
William Passo is the CEO of Rain AI, having previously served as the company's COO. He took over the CEO role from co-founder Gordon Wilson in 2023. His background is in law and business operations.
Official website: https://rain.ai/