Nir Zuk

Background

Nir Zuk was born in Rehovot, Israel ¹. He received his first computer — a Dragon 64 — in his youth and taught himself programming at age 16 ¹. He served in the Israel Defense Forces, working in Unit 8200, the signals intelligence branch of the Israeli Intelligence Corps, where he led software development ^{2 3}. While serving, he began university studies in mathematics but never completed a degree ¹.

Zuk joined Check Point Software Technologies in 1994 as a principal engineer and was one of the developers of stateful inspection technology, a foundational advance in network security ^{2 3}. He spent approximately four and a half years at Check Point, including two years in Israel and two and a half in the United States ¹. He left in mid-1999 after growing frustrated with what he described as a shift toward bureaucracy over innovation ¹.

In March 1999, Zuk co-founded OneSecure, a managed services company that pivoted during the dot-com crash to build the first intrusion prevention system ^{1 3}. NetScreen Technologies acquired OneSecure for $45 million in stock in 2002 ¹. Zuk became CTO of NetScreen, which was subsequently acquired by Juniper Networks in 2004 ^{2 3}.

In 2005, Zuk founded Palo Alto Networks with $9.4 million in venture capital from Greylock Partners and Sequoia Capital, bringing approximately 25 people from Juniper to build a next-generation firewall ^{1 4}. The company pioneered the next-generation firewall category and grew into the world’s largest cybersecurity company, with a market capitalization exceeding $120 billion ^{5 6}. In August 2025, Palo Alto Networks announced Zuk’s retirement after more than 20 years as founder and CTO ⁷.

Forbes estimates Zuk’s personal fortune at approximately $1.5 billion ⁸. After two decades in California, he moved back to Israel during the Covid-19 pandemic and purchased a home in the Tzahala neighborhood of Tel Aviv ⁹. Over the four years since his return, he has invested nearly $150 million of his own money in Israeli startups across fintech, healthtech, and defense tech ⁵.

In March 2026, Zuk unveiled Cylake, a new cybersecurity startup developing an AI-native data sovereignty platform, which raised $45 million in seed funding led by Greylock Partners ^{10 11}. His co-founders are Wilson Xu, a longtime Palo Alto Networks engineering leader, and Ehud (Udi) Shamir, co-founder of SentinelOne ¹⁰.

Stated Thesis

Zuk has publicly described his Israeli investment approach as “philanthropy with a chance of profit or self-sustainability” ¹². He has stated: “There is a higher risk in Israel, but that also means valuations are low” and “It’s hard to raise money, so you can get a big chunk of a company for a relatively low amount of money” ⁵.

He has noted that he deliberately avoids investing in cybersecurity startups as an angel due to potential conflicts of interest with Palo Alto Networks, instead backing ventures in finance, healthcare, and defense ⁵. He has said: “Israel has a great advantage in fintech, health tech, and defense tech” ⁵.

On entrepreneurship broadly, Zuk has stated: “An A-team with a C business plan is better than a C-team with an A business plan. The business plan will come, but the team is everything” ⁵. He has also said: “I like being told that it’s very difficult to do something. It mainly means that if I succeed, then no one else will be able to do it” ⁹.

He has expressed a strong preference for founders building large, sustainable businesses: “If your business plan doesn’t call for a big, sustainable business you will probably fail. If you find yourself building a business because you want to sell it for $100 million and walk away with $10 million for yourself, you will end up with a lousy $10 million company” ⁴.

Inferred Thesis

Based on 7 verified investments and ventures. Zuk’s angel and personal investing activity is relatively concentrated because he deployed large checks into a small number of companies, totaling nearly $150 million over four years ⁵. Sample size is small; qualitative patterns are described rather than percentages.

Sector distribution (7 verified investments/ventures): - Fintech: 2 of 7 — Esh (digital banking), Finq (AI-driven investment platform) - Healthtech: 1 of 7 — Bariks Health (portable hyperbaric chambers) - Defense tech / aerospace: 1 of 7 — Lowental Hybrid (UAV propulsion) - Cybersecurity: 1 of 7 — Fireblocks (crypto security infrastructure; seed-stage) - Transportation: 1 of 7 — Air Haifa (regional airline) - Media: 1 of 7 — Relevant (TV channel; closed after less than one year)

Note: Cylake (founded March 2026) is excluded from the angel portfolio as it is a company Zuk founded and serves as CEO, not an angel investment. His LP position in Cyberstarts is also excluded as it is a fund commitment, not a direct investment.

Stage distribution: Zuk invests primarily at seed and early stages, writing large personal checks. His investment in Finq was a $6 million angel round ¹³. He led a $7 million round in Bariks Health ¹⁴. He is the sole investor in Air Haifa, owning 57% of the company ¹².

Check size: Zuk writes exceptionally large individual checks for an angel investor, ranging from approximately $5 million (Lowental Hybrid co-investment) to tens of millions (Air Haifa). His total deployed capital of ~$150 million across a small portfolio implies an average check well above $10 million ⁵.

Geographic concentration: All verified angel investments are in Israeli companies. Zuk has explicitly tied his investment activity to his return to Israel and a desire to support the Israeli economy ^{9 5}.

Founder profile patterns: Zuk backs founders with deep domain expertise and is willing to invest in sectors far outside his cybersecurity background — airlines, digital banking, medical devices, drone propulsion. He appears to favor founders tackling problems considered difficult or unconventional ⁹.

Co-investor patterns: Zuk frequently invests alongside Israeli government bodies (Israel Innovation Authority in both Bariks Health and Lowental Hybrid) and Israeli institutional investors. In Lowental Hybrid, he co-invested with Ace Capital Partners ¹⁵. He is a limited partner in Cyberstarts alongside prominent Israeli cyber founders including Shlomo Kramer, Marius Nacht, and Mickey Boodaei ¹⁶.

Notable pattern: Zuk explicitly avoids cybersecurity angel investments to prevent conflicts of interest with Palo Alto Networks ⁵. His one crypto-security investment (Fireblocks seed in 2018) was early enough to predate this stated policy. This is unusual for a cybersecurity titan — most prominent cyber founders (e.g., Shlomo Kramer, Gili Raanan) invest heavily in the sector.

Notable gap: Despite investing ~$150 million, Zuk’s portfolio is concentrated in only about 7 known companies, suggesting he makes very few, very large bets rather than spreading capital across dozens of startups.

Portfolio

This table includes 7 verified investments and personal ventures. Zuk has stated he invested nearly $150 million in Israeli startups over four years ⁵; this table likely represents his full direct investment portfolio given the large check sizes involved.

Additionally, Zuk is a limited partner in Cyberstarts, the cybersecurity seed fund founded by Gili Raanan, which was an early investor in Wiz ¹⁶.

In Their Own Words

“The industry has overrotated toward delivering everything in the cloud, and that has left many of the most important customers stuck 20 years behind.” — Nir Zuk, CTech interview, March 2026 ⁸

“Cybersecurity is constantly evolving, and sometimes new challenges demand completely new approaches. Cylake is for institutions where maintaining full control over data and operations is not optional.” — Nir Zuk, Cylake launch announcement, March 2026 ¹¹

“I really understand how difficult it is to turn down such an offer. But personally, I truly enjoy being the founder, CTO, and a board member of a public company worth $120 billion — a company that, by the way, began its public journey with a valuation of just $2 billion.” — Nir Zuk, on the Google-Wiz $32B acquisition, CTech interview, 2025 ⁶

“I understand that it’s almost impossible to say no to $32 billion, but for Israel, it would have been better if Wiz had held out a little longer and gone public in New York.” — Nir Zuk, CTech interview, 2025 ⁶

“There is a higher risk in Israel, but that also means valuations are low. It’s hard to raise money, so you can get a big chunk of a company for a relatively low amount of money.” — Nir Zuk, CTech interview, 2025 ⁵

“I like being told that it’s very difficult to do something. It mainly means that if I succeed, then no one else will be able to do it.” — Nir Zuk, Globes interview, 2024 ⁹

“An A-team with a C business plan is better than a C-team with an A business plan. The business plan will come, but the team is everything.” — Nir Zuk, CTech interview, 2025 ⁵

“If everybody believes it shouldn’t be done, or it cannot be done, or nobody would want it, then you know it’s a good reason to do it.” — Nir Zuk, Sequoia Capital podcast, 2024 ⁴

“The cybersecurity industry will experience tectonic shifts in 2025. These historic transformations will see the convergence of AI, data and platform unification.” — Nir Zuk, Cybersecurity Ventures interview, 2025 ³

“We can’t keep relying on cyber as the engine of Israeli high-tech — and therefore the economy.” — Nir Zuk, Calcalist interview, 2025 ¹⁹

“Embrace the disruption. If you don’t embrace the disruption, you will end up like companies that didn’t embrace the disruption.” — Nir Zuk, Sequoia Capital podcast, 2024 ⁴

What Founders Say

Eldad Tamir, founder and CEO of Finq, described Zuk’s $6 million investment as “the beginning of a new financial world in Israel — smart, digital, and objective” ¹³.

No other independently sourced founder testimonials found. Zuk’s angel portfolio is relatively small and concentrated in Israeli companies with limited English-language coverage of founder-investor relationships.

The following investor-side quotes provide context on how collaborators view him:

“Nir Zuk is a once-in-a-generation founder whose innovation has redefined cybersecurity and elevated the entire industry. His achievements will resonate for decades.” — Richard Seewald, Founder & Managing Partner, Evolution Equity Partners, Cybersecurity Ventures, 2025 ³

“The next generation of cybersecurity will be AI-native, agentic and built on holistic data and context. Cylake is focused on a segment of the market where security must operate under full control to meet regulatory and operational reality.” — Asheem Chandna, Partner, Greylock Partners, on investing in Zuk’s Cylake, March 2026 ¹¹

Connections

• Board member, Bariks Health — joined the board alongside his personal investment in July 2025 ¹⁴
• Co-founder and controlling shareholder (13%), Esh Bank — alongside Yuval Aloni (co-founder/CEO, 18%), Alex Liverant (DoubleVerify founder), and Shmuel Hauser (former Israel Securities Authority chairman). Esh sold to Isracard at approximately $130 million valuation in March 2026 ^{20 18}
• LP, Cyberstarts — alongside Shlomo Kramer (Check Point co-founder), Marius Nacht (Check Point co-founder), and Mickey Boodaei (Trusteer founder) in Gili Raanan’s cybersecurity seed fund ¹⁶
• Co-founder, Cylake — alongside Wilson Xu (former Palo Alto Networks engineering leader) and Ehud “Udi” Shamir (SentinelOne co-founder), backed by Greylock (Asheem Chandna) ¹⁰
• Former CTO and board member, Palo Alto Networks (2005-2025) — worked with CEO Nikesh Arora; backed by Sequoia Capital (Jim Goetz) and Greylock Partners (Asheem Chandna) ^{7 4}
• Former principal engineer, Check Point Software Technologies (1994-1999) — one of the first three employees ^{1 21}
• Co-founder, OneSecure — alongside Rakesh Loonkar; acquired by NetScreen Technologies in 2002 ^{1 22}
• Founder, Relevant — Israeli streaming media channel, with Modi Frydman (former Channel 10 CEO) and Lior Schleien (TV producer) ²³

Sources