Harmonic Raises $120 Million Series C
PALO ALTO — Harmonic, an artificial intelligence lab leading the development of Mathematical Superintelligence (MSI), has raised $120 million Series C funding round at a $1.45 billion post-money valuation. This round is led by Ribbit Capital with significant participation from Sequoia Capital, Index Ventures, Kleiner Perkins and Emerson Collective as a new investor. Robinhood CEO Vlad Tenev is a founder of the company.
Harmonic’s flagship Aristotle model recently achieved gold-medal level performance at the International Mathematical Olympiad, considered the most prestigious mathematical competition in the world, and is now available to the public. Unlike other models, Aristotle makes use of formal verification using Lean4 to ensure accuracy and eliminate hallucinations. In the first few weeks since its API beta launch, Aristotle has already been used by mathematicians and researchers to accelerate progress and create novel discoveries. Last week, Harmonic rolled out major upgrades, including support for plain English input (in addition to native Lean4), automated lemma generation, and a streamlined terminal interface.
“Aristotle’s gold-medal performance at the IMO offered an early glimpse into what Mathematical Superintelligence makes possible with advanced reasoning and formal verification together in a single system,” said Tudor Achim, CEO of Harmonic. “This funding allows us to advance that foundation even further and faster, while aggressively deploying Aristotle across industries where reliability is critical.”
“The Harmonic team is achieving extraordinary success in showing how MSI can accelerate progress in mathematics and other quantitative fields, and Aristotle, even in its early form, already gives us a glimpse towards the better future we will all be in once advanced reasoning and formal verification fully merge,” said Vlad Tenev, Co-Founder and Executive Chairman of Harmonic.
“Ribbit’s renewed investment reflects the tremendous technical achievements Harmonic has already made,” said Nick Shalek, General Partner at Ribbit Capital. “We’re proud to deepen our partnership as Aristotle continues to demonstrate what Mathematical Superintelligence can achieve in the real world.”
Harmonic previously raised $100 million in its July 2025 Series B funding round led by Kleiner Perkins, and $75 million in its September 2024 Series A, which was led by Sequoia Capital and included significant participation from Index Ventures. Additional backers include Paradigm and Era Funds.
