Harmonic has raised a $120 million Series C round, pushing the company’s valuation to $1.45 billion as it accelerates development of its Mathematical Superintelligence platform. The round is led by Ribbit Capital, with participation from existing investors Sequoia Capital, Index Ventures, and Kleiner Perkins, as well as the addition of Emerson Collective.
Based in Palo Alto, Harmonic is building a math-rooted artificial intelligence system designed to guarantee accuracy through formal verification. The new funding supports the company’s push to expand its flagship model Aristotle, which recently reached a significant milestone by achieving gold-medal level performance at the International Mathematical Olympiad. Harmonic has made Aristotle publicly available and positioned it as a model capable of eliminating hallucinations through its integration with Lean4.
Since launching its API beta, Aristotle has been rapidly adopted by mathematicians and researchers seeking to accelerate complex reasoning and discovery. The company has also introduced a series of feature upgrades, such as automated lemma generation, a simplified terminal interface and support for plain-English inputs alongside native Lean4.
The Series C round builds on the company’s substantial fundraising momentum. Harmonic previously raised a $100 million Series B round in July 2025, led by Kleiner Perkins, and a $75 million Series A round in September 2024, led by Sequoia Capital, with participation from Index Ventures. Additional backers include Paradigm and Era Funds.
Founded in 2023, Harmonic is backed by Robinhood CEO Vlad Tenev and led by CEO Tudor Achim. The company describes its mission as building Mathematical Superintelligence, a new class of artificial intelligence rooted in mathematical reasoning to ensure accuracy and eliminate hallucinations across industries where reliability is essential.
KEY QUOTES:
“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. This funding allows us to advance that foundation even further and faster, while aggressively deploying Aristotle across industries where reliability is critical.”
Tudor Achim, CEO of Harmonic
“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.”
Vlad Tenev, Co-Founder and Executive Chairman of Harmonic
“Ribbit’s renewed investment reflects the tremendous technical achievements Harmonic has already made. We’re proud to deepen our partnership as Aristotle continues to demonstrate what Mathematical Superintelligence can achieve in the real world.”
Nick Shalek, General Partner at Ribbit Capital
