Thomas Seifert
About Thomas Seifert
Thomas Seifert has been Chief Financial Officer of Cloudflare since June 2017. Cloudflare is an internet performance and security company. Before that he held executive roles at Symantec, Brightstar and Advanced Micro Devices, and earlier at Infineon Technologies, Qimonda and a wireline communications business group.
He has served on public company boards. He was a director of IPG Photonics from July 2014 to February 2023, and he has been a director of First Derivatives since July 2020.
He holds an MBA from Friedrich Alexander University Erlangen-Nürnberg in Germany. He also holds a master's degree in economics (one source says mathematics and economics) from Wayne State University.
Little of Seifert's angel activity is public. The one round we could confirm is Arito AI's seed in May 2026, where press coverage names him among the finance executives who invested. We did not find a public list of other angel investments, a fund, or any stated check sizes.
Arito AI is a Tel Aviv and Palo Alto based startup founded in 2025 by Daniel Zahavi and Michael Estrin. It raised a $6M seed round led by Amplify Partners, announced in May 2026. Two CFOs joined the round as angel investors, and Seifert is named in coverage of it.
Arito builds an agentic analytics platform for finance and revenue teams. It uses natural language, automatically updating dashboards and AI alerts, and it states a focus on governance and role-based access control. The Lounge deals desk lists this round twice, as "Arito Seed" and "Arito AI Seed", both at $6M in May 2026. Both entries appear to describe the same financing.
Seifert has not published an investment thesis, target stage or check size that we could find. His one confirmed AI investment is a seed-stage enterprise software company selling to finance teams, which matches his background as a public company CFO. This is an observation from a single deal. It is not a stated mandate, and no geographic focus is public.
- Arito AI: agentic analytics platform for finance and revenue teams; $6M seed led by Amplify Partners, May 2026, with Seifert as an angel participant
- thesaasnews.com/news/arito-ai-raises-6-million-seed-round
- app.dealroom.co/news/feed/arito-ai-raises-6m-to-bring-agentic-analytic
- streetinsider.com/Evertise+Financial/The+Analytics+Gap+Is+Real.+Arito+
- caplight.com/company/arito
- clay.com/dossier/cloudflare-cfo
- insidertrades.com/cloudflare-inc-stock/thomas-j-seifert
Investing activity
Thomas Seifert appears in 2 AI deals tracked by the Lounge deals desk. The rounds are mostly Seed, with a median round size of $6M. The most recent are Arito AI (Seed, $6M, May 2026) and Arito (Seed, $6M, May 2026).
Thomas Seifert most often invests alongside Amplify Partners, and the companies they back on Lounge are mostly in AI.
Deals
Frequently asked questions about Thomas Seifert
Who is Thomas Seifert?
Thomas Seifert is the Chief Financial Officer of Cloudflare, a role he has held since June 2017. He previously held executive roles at Symantec, Brightstar and AMD.
Has Thomas Seifert invested in AI startups?
Yes. He participated as an angel in Arito AI's $6M seed round in May 2026, which Amplify Partners led. We found no other AI investments of his in public sources.
What check size does Thomas Seifert write?
His check size is not public. He did not disclose his amount in the Arito AI round, and we found no public statement of his typical checks.
What stage and sectors does Thomas Seifert back?
The only confirmed investment is a seed round in enterprise AI for finance and revenue teams. He has not published a stated stage or sector focus.
Should founders pitch Thomas Seifert?
Founders building AI software for CFOs and finance or revenue teams have the closest fit with his one known investment. He has no public pitch process, so a warm introduction through his network is the likely route.
Is Thomas Seifert an angel investor?
Yes. Thomas Seifert invests personally as an angel.
What AI companies has Thomas Seifert invested in?
Thomas Seifert's AI investments include Arito AI and Arito. The 2 rounds on Lounge are listed on this page with amounts, dates and co-investors.
What stage does Thomas Seifert invest at?
In the rounds tracked on Lounge, Thomas Seifert has invested at Seed, with a median round of $6M.
Who does Thomas Seifert co-invest with?
Thomas Seifert's most frequent co-investors on Lounge are Amplify Partners (2 deals).
How can founders reach Thomas Seifert?
Founders on Lounge can see Thomas Seifert's contact details in AI Investor Contacts (paid plans), check for a warm introduction through members who worked with them under Warm Paths, and add Thomas Seifert to their Investor Pipeline to track the conversation.