Bill Gross

Founder & CEO ProRata

Last Reviewed: September 25, 2026

Executive Summary

Bill Gross is the founder and chief executive of ProRata, a Pasadena company that licenses content from publishers for AI search and pays them half the revenue it earns. He launched it in 2024 from Idealab, the technology incubator he founded in 1996 and still chairs. ProRata’s attribution technology is meant to work out which sources contributed to an AI-generated answer and share revenue with them in proportion. Its Gist products bring that to a consumer answer engine, to AI search embedded on publishers’ own sites, and to advertising placed alongside AI answers. It has raised more than $75 million, including a $40 million Series B led by Touring Capital in September 2025. Gross has started companies for four decades, from a natural-language add-on for Lotus 1-2-3 to GoTo.com, the search-advertising company later known as Overture, and the renewable-energy company Heliogen. This is the Idealab founder, not the bond investor Bill Gross.

Career Highlights

• Founder and CEO of ProRata, named as such on the company’s home page and in its September 2025 funding release.
• Launched ProRata in August 2024 with $25 million and early support from the Financial Times, Universal Music Group, The Atlantic, Axel Springer and Fortune. Closed a $40 million Series B in September 2025 and launched Gist Answers.
• Founded Idealab in March 1996 and ran it as CEO until the end of 2017. Idealab now lists him as chairman and says it has created more than 145 companies with more than 45 IPOs and acquisitions.
• Conceived GoTo.com, later Overture Services, which agreed to merge with Yahoo! in July 2003.
• CEO of Heliogen for most of 2013 to 2023, taking it public on the NYSE in December 2021. The board terminated him as CEO in February 2023.
• Director of Energy Vault, another company he started, until March 2025.
• Sold his first company, GNP Development, to Lotus Development Corporation in 1985, and later founded Knowledge Adventure.

Professional Journey

Gross started his first business, a solar venture, in high school. He then studied mechanical engineering at Caltech. After graduating he founded GNP Development, which made HAL, a natural-language interface for the Lotus 1-2-3 spreadsheet. Lotus Development Corporation bought the company in 1985. In 1991 he started Knowledge Adventure, an educational software publisher later sold to Havas/Vivendi.

In March 1996 he founded Idealab in Pasadena, originally under the name Bill Gross’ Idealab. The model was to generate ideas internally, test many in parallel, and spin the promising ones out as companies with their own teams. Idealab’s own count is more than 145 companies. The best known of Gross’s own ideas there was GoTo.com, a search-advertising business. ProRata describes him as the inventor of pay-per-click keyword advertising. GoTo.com became Overture Services, and in July 2003 Overture agreed to merge with Yahoo!. Idealab and Gross were among its reporting shareholders. Heliogen’s proxy also lists CarsDirect.com / Internet Brands, Energy Vault and Carbon Capture among the companies he conceived and started. He ran Idealab as chief executive until the end of 2017, then became CEO and chairman of Idealab Studio from January 2018. Idealab today names him chairman, with Marcia Goodstein as chief executive.

Clean energy took up much of the following decade. Gross was chief executive of the renewable-energy technology company Heliogen from 2013 to early 2015 and again from 2016. He took it public through a merger with a special-purpose acquisition company in December 2021, becoming CEO and chairman of the listed company. On 5 February 2023 Heliogen’s board terminated him as chief executive. The board cited the company’s decline in market value since listing, and Gross’s resignation letter objected to its choice of successor. He left the board the same day. He also sat on the board of Energy Vault, an energy-storage company he had helped start, until March 2025.

ProRata came out of Idealab Studio in August 2024. Gross framed it as a fix for how AI answer engines treat publishers, whose content he said those engines were using without credit or payment. ProRata’s technology attributes AI-generated answers to the sources that contributed to them and shares revenue with rights-holders, 50/50 on a per-use basis. It launched with $25 million and early backing from the Financial Times, Universal Music Group, The Atlantic, Axel Springer and Fortune, followed by a consumer answer engine, Gist. In September 2025 it closed a $40 million Series B led by Touring Capital. Mayfield, Revolution Ventures, Prime Movers Lab, SBI Investment, dmg media and Idealab Studio are among its backers. It also launched Gist Answers, which lets publishers embed AI search on their own sites, alongside Gist Ads, which places conversational advertising next to AI answers. By then more than 700 publications had licensed content to the network.

Idealab’s biography of him lists him as a member of the Board of Trustees of Caltech and of the Art Center College of Design.

Education

California Institute of Technology

B.S. in Mechanical Engineering