Robinhood CEO's AI math startup valued at nearly $900 million

Los Angeles Times

11-07-2025

Harmonic AI, an artificial intelligence startup co-founded by Robinhood Markets Inc. Chief Executive Officer Vlad Tenev, has raised $100 million in funding to tackle a problem that has sometimes confounded AI models: math.
The Series B funding round was led by Kleiner Perkins, with participation from Sequoia Capital, Index Ventures and Paradigm. The deal values the AI startup at $875 million, said Tenev, who serves as the company's executive chairman, a non-operating role. Harmonic's CEO is Tudor Achim, who previously led autonomous driving startup Helm.ai.
Founded in 2023 by Tenev and Achim, the Palo Alto, California-based startup aims to build AI systems that can solve complex math problems, creating what the company refers to as mathematical superintelligence. Harmonic plans to make its flagship AI model, Aristotle, available to researchers and the general public later this year.
'The near-term goal is to build an AI that solves math problems at a level that is superior to any human,' Tenev told Bloomberg News. 'The ultimate goal would be to solve major unsolved mathematical problems and expand that to problems in physics and computer science.'
Tenev said Harmonic's math-first approach should give it an advantage over large language models, which underpin AI chatbots and are generally not as adept at solving complicated math problems. Harmonic also seeks to eliminate the issue of hallucinations, or when a chatbot makes up information, by relying on formal verification, a mathematical method used to guarantee an AI system functions correctly.
'We can ensure that every piece of output and every step in our model's reasoning is verifiably correct,' Tenev said. 'That is just a very different approach to building AI models that I think is going to be the approach that dominates in the future.'
Harmonic previously raised $75 million from Sequoia and Index. Its new funding round gives the company a valuation just under the $1 billion threshold that would make it a 'unicorn.' Tenev said that was an intentional choice.
'You never want to take the highest offer,' said Tenev, who raised billions in funding for Robinhood before the stock-trading service's 2021 initial public offering. 'Optimizing for valuation is never the right choice.'
Clark writes for Bloomberg.