British startup Synthesia, whose AI platform helps companies create interactive training videos, has raised a $200 million Series E round of funding that brings its valuation to $4 billion — up from $2.1 billion just a year ago.

Unlike some other AI startups that are still a long way from turning a profit, Synthesia has found a lucrative business in transforming corporate training thanks to AI-generated avatars. With enterprise clients including Bosch, Merck, and SAP, the London-based company crossed $100 million in annual recurring revenue (ARR) in April 2025.

This milestone explains why Synthesia’s venture backers are literally doubling down. The Series E that nearly doubled its valuation was led by existing investor GV (Google Ventures), with participation from several other previous backers — including Series B lead Kleiner Perkins, Series C lead Accel, Series D lead New Enterprise Associates (NEA), NVIDIA’s venture capital arm NVentures, Air Street Capital, and PSP Growth. 

Aside from ongoing support, this round will bring both new and departing investors. On one hand, Matt Miller’s VC firm Evantic and the secretive VC firm Hedosophia are joining the cap table as new entrants. On the other hand, Synthesia will facilitate an employee secondary sale in partnership with Nasdaq, TechCrunch has learned.

To be clear, Synthesia isn’t going public just yet — Nasdaq isn’t acting as a public exchange in this operation, but as a private markets facilitator that will help early team members turn their shares into cash. These employee stock sales often happen outside of this framework, but usually at prices either below or above the company’s official valuation, and are sometimes frowned upon by other shareholders. With this process, all sales will be tied to the same $4 billion valuation as Synthesia’s Series E, while the company keeps an element of control.

“This secondary is first and foremost about our employees,” Synthesia CFO Daniel Kim told TechCrunch. “It gives employees a meaningful opportunity to access liquidity and share in the value they’ve helped create, while we continue to operate as a private company focused on long-term growth.”

For Synthesia, this long-term growth involves going beyond expressive videos and embracing the AI agents trend. According to a press release, the company is developing AI agents that will let its clients’ employees “interact with company knowledge in a more intuitive, human-like way by asking questions, exploring scenarios through role-play, and receiving tailored explanations.”

The company said early pilots have received positive feedback from customers, who reported higher engagement and faster knowledge transfer compared to traditional formats. This positive response explains why Synthesia now plans to make agents a “core strategic focus” to invest in, alongside further product improvements to its existing platform.

While it didn’t disclose revenue forecasts, the company hopes its platform will offer a welcome answer to the struggles of enterprises in keeping their workforce adequately trained despite rapid changes. “We see a rare convergence of two major shifts: a technology shift with AI agents becoming more capable, and a market shift where upskilling and internal knowledge sharing have become board-level priorities,” Synthesia’s co-founder and CEO Victor Riparbelli said in a statement.

Seeing boards care more about employees as a result of AI wasn’t on anyone’s bingo card, except perhaps Riparbelli. Together with his cofounder, Synthesia COO Steffen Tjerrild, Riparbelli took the initiative of conducting a secondary sale so that employees could share in the success of the unicorn company. Founded in 2017, Synthesia now has more than 500 team members, a 20,000-square-foot HQ in London, and additional offices in Amsterdam, Copenhagen, Munich, New York City, and Zurich.

While unusual for a British startup, this coordinated secondary sale isn’t a first and likely not a last, Synthesia’s head of corporate affairs and policy, Alexandru Voica told TechCrunch. “My guess is that as [U.K.-based] private companies stay private longer, this type of structured, cross-border employee liquidity may become increasingly common, so I wouldn’t be surprised to see others do it, either with Nasdaq or others,” he predicted.