Harry Nelis

Background

Harry Nelis is a Partner at Accel, based in London, where he joined in 2004 as one of the firm’s first London-office hires ¹². He focuses on software, fintech, and consumer internet investments across Europe and beyond ¹.

Nelis began his career as an engineer at Hewlett-Packard Labs in Palo Alto, California ¹³. He then founded E-motion, a venture-backed software collaboration company in Silicon Valley ¹³⁴. Before joining Accel he held two finance roles: an advisory position at Goldman Sachs where he advised technology companies on corporate finance and M&A transactions, and an investing role at Perry Capital, a large US hedge fund, where he invested in public technology and media companies ⁴.

He holds a PhD and MS in Electrical Engineering from Delft University of Technology (the Netherlands) and an MBA with distinction from Harvard Business School ¹³⁴. He is originally from the Netherlands ¹.

Nelis has appeared on the Forbes Midas List of top 100 global venture investors ⁴. He has been a Partner at Accel’s European operation since 2004, spanning multiple European fund vintages including Accel’s eighth European fund, a $650 million vehicle closed in May 2024 ⁵.

Stated Thesis

(Self-reported. These represent what Nelis says publicly about his investing approach. See Inferred Thesis for analysis of actual behavior.)

Nelis publicly describes his focus as software, fintech, and consumer internet companies at early and growth stages ¹. He describes himself as having a “founder-first approach to venture capital” shaped by his own experience as a founder, and thinks of himself “as a coach and advisor to world-class companies” ³. He is “a strong believer in founders leading their own companies” ³.

On identifying outlier investments, Nelis has stated: “The biggest mistake in venture is not losing money on an investment. It is missing the outlier.” He has also said: “The hardest thing is to live with the knowledge that very likely you can be wrong” ⁶.

On what he looks for in candidates and founders: he asks “What’s the riskiest thing that you’ve ever done in your life?” and says the answer must reflect strategic risk-taking, not accidental stumbling — “what do I get when it goes well?” ⁶.

On what separates exceptional founders: “What separates them is the calibre of the entrepreneurs involved… Great founders have both the desire, and crucially the ability, to attract those people [great executives]. What separates the very best is their ability to learn and improve.” ⁷

On Europe as a startup ecosystem: “Many entrepreneurs have realised that Europe is a great place to start a business… Entrepreneurship is a people business… Great companies can emerge from anywhere.” ⁸

On AI as a category: “I see it more like the Internet boom that happened in 1999. People realize that this is a fundamental change in technology. There are many, many opportunities in that.” ⁸

Accel’s eighth European fund (2024) targets up to 30 investments over a three-year deployment period, with initial tickets of $1M–$20M at seed and Series A, with reserves to follow on ⁵.

Inferred Thesis

The analysis below is based on 18 verified investments from Accel’s portfolio pages, press coverage, and investment announcements ^{91011121314151617181920212223242526}. This represents a partial view of his full investment history given Accel’s broad portfolio.

Sector concentration (based on 18 verified investments): - Fintech / payments / financial infrastructure: 6 of 18 (33%) — Funding Circle, WorldRemit/Zepz, CHECK24, Super Payments, Taxdoo, Showroomprive - Enterprise software / SaaS / developer tools: 7 of 18 (39%) — Celonis, Instana, Dash0, Callsign, Gravity Sketch, Carto, Personio - Consumer internet / travel: 2 of 18 (11%) — KAYAK, Showroomprive (dual-category) - Collaboration / productivity: 1 of 18 (6%) — Miro

Note: sample size is 18 verified investments; Nelis has led many more investments over 20+ years at Accel. These percentages are directional only.

Stage distribution: The majority of verified investments are at Series A (Celonis, Miro, Callsign, Instana, Taxdoo, Carto, Gravity Sketch, Personio) or early growth rounds (Funding Circle Series C, WorldRemit Series A). Nelis has also led seed rounds (Dash0 seed in 2024) and later-stage follow-ons (Zepz Series F in 2024). His stated check range of $15M–$70M reflects a focus on Series A and growth, though he participates across stages within existing portfolio companies ¹⁵.

Geographic concentration: Portfolio companies are predominantly European, with a strong tilt toward the UK (Funding Circle, WorldRemit/Zepz, Callsign, Super Payments), Germany (Celonis, Instana, Dash0, Taxdoo, CHECK24, Personio), France (Showroomprive), and Spain (Carto). One US investment (KAYAK) dates to early in his career.

Founder profile patterns: - Technical founders: Celonis (TU Munich spin-off; three technical co-founders), Instana/Dash0 (Mirko Novakovic, serial technical founder), Callsign (AI authentication), Carto (GIS technology specialists) - Repeat founders: Samir Desai (Funding Circle → Super Payments — Nelis backed both), Mirko Novakovic (Instana → Dash0 — Nelis backed both). The repeat-founder pattern is particularly strong in his portfolio. - Deep domain expertise: Taxdoo founders included a former German Ministry of Finance VAT expert; Instana team had “decades of experience in the APM market” ¹³

Co-investor patterns: From verified rounds: 83North (Celonis Series A), Target Partners (Instana), Lightspeed Venture Partners (Personio), Union Square Ventures (Super Payments), TCV (Zepz), LeapFrog (Zepz), Earlybird Ventures and Kibo Ventures (Carto).

Notable behavioral patterns: - Strong loyalty to repeat founders — two documented cases of backing the same founder across two companies (Desai, Novakovic) - Willingness to lead very large follow-on rounds: led Zepz Series F at $267M in 2024 ²⁴; co-led Funding Circle’s $100M round in 2017 ²⁵ - Multiple IPO outcomes: KAYAK (NASDAQ), Showroomprive (Euronext Paris), Funding Circle (LSE) — more exits via public markets than typical for a European VC partner

Portfolio

This table covers 17 investments from 18 verified entries (Zepz appears twice as initial 2014 investment and 2024 follow-on). Accel has invested in more than 200 companies in Europe and Israel; this table captures verified investments specifically attributed to Nelis and is not a complete accounting of all his investment activity over 20+ years at the firm.

In Their Own Words

On the biggest risk question as investment philosophy:

“The biggest mistake in venture is not losing money on an investment. It is missing the outlier.” — Harry Nelis, Fortune, March 2025 ⁶

“The hardest thing is to live with the knowledge that very likely you can be wrong.” — Harry Nelis, Fortune, March 2025 ⁶

“Typically, people who have done well in school and done well in their careers, they don’t like getting it wrong. But in our business, you need to get it wrong a few times to get it right.” — Harry Nelis, Fortune, March 2025 ⁶

On what makes great founders (from the Funding Circle IPO analysis):

“What separates them is the calibre of the entrepreneurs involved.” — Harry Nelis, “Funding Circle’s IPO: The Founder Factor,” Accel, 2018 ⁷

“Great founders have both the desire, and crucially the ability, to attract those people.” — Harry Nelis, “Funding Circle’s IPO: The Founder Factor,” Accel, 2018 ⁷

“What separates the very best is their ability to learn and improve.” — Harry Nelis, “Funding Circle’s IPO: The Founder Factor,” Accel, 2018 ⁷

On the European tech ecosystem:

“These founder factories are the things that give birth to new companies. It’s kind of a reproductive organ in a way.” — Harry Nelis, French Tech Journal interview ²⁷

“Many entrepreneurs have realised that Europe is a great place to start a business.” — Harry Nelis, AEEN interview ⁸

On the Personio investment (2020):

“While software entrepreneurs have traditionally overlooked developing solutions for SMEs, Personio has recognised this large and growing market of customers hungry for better solutions for their businesses.” — Harry Nelis, Personio Series C announcement, January 2020 ¹⁹

“Having had the chance to meet and work with Hanno and his team over the past few months, it’s remarkable to see how they’ve built a fast growing company and a great product, both with relentless focus on the customer.” — Harry Nelis, Personio Series C announcement, January 2020 ¹⁹

On the Taxdoo investment (2020):

“By bringing together transaction data from across marketplaces, payments, and accounting platforms, we believe that Taxdoo is ideally positioned to build a category leader as the compliance core for e-commerce.” — Harry Nelis, Accel blog, December 2020 ²⁰

On the Callsign investment (2017):

“With the rise in cybercrime, businesses have been stuck between a rock and a hard place, having to choose security solutions that either offer a poor user experience or not enough protection. With Callsign, they don’t have to compromise.” — Harry Nelis, Callsign Series A announcement, July 2017 ¹⁶

On the Celonis investment (2016):

“We are very excited to be working with the Celonis team and helping them achieve their ambitious goals in building the process mining category globally.” — Harry Nelis, Munich Startup, June 2016 ¹⁵

On the Carto investment (2015):

“We have been extremely impressed by the CartoDB founding team’s depth of expertise, and how they’ve been able to change the historically complex GIS analytics market into something that any business analyst can navigate.” — Harry Nelis, CartoDB Series B announcement, September 2015 ¹⁴

On the Super Payments investment (2022):

“A second-time founder in the fintech space, Samir has the ambition, industry knowledge, focus and team required to build a company at scale. I’m delighted to be joining forces with Super on the next phase of its journey and continuing a long partnership with Samir.” — Harry Nelis, Tech.eu, August 2022 ²²

On the Showroomprive IPO (2015):

“Since investing five years ago, it’s been fantastic to be a part of Showroomprivé’s rapid and profitable growth. When I first met Thierry and David, I was impressed by their blend of experience; they brought together the technology and retail experience necessary to build a successful online fashion retailer that was profitable from inception.” — Harry Nelis, Tech.eu, October 2015 ²⁸

On the Instana acquisition by IBM (2020):

“We’ve only been shareholders for a bit more than 3 years and in many ways our journey was just getting started.” — Harry Nelis, Accel, “Onwards, Instana,” November 2020 ¹⁷

On the Dash0 seed investment (2024):

“Dash0 is revolutionizing observability and taking advantage of a major opportunity in the market at the same time.” — Harry Nelis, Dash0 seed announcement, November 2024 ²³

On WorldRemit’s focus on underserved remittance corridors (2014):

“We like their focus on the long tail, and on the smaller corridors. Instead of focusing on Sterling to euro or to U.S. dollars, what WorldRemit does is think of how to service, for example, Filipinos in Norway remitting back to the Philippines.” — Harry Nelis, TechCrunch, March 2014 ¹³

What Founders Say

Ismail Ahmed, Co-founder and CEO, Zepz (formerly WorldRemit):

“When Accel invested in the Series A in 2014, we were a very small, obscure startup…we certainly made the right choice in VCs.” — Ismail Ahmed, Accel blog interview ²⁹

“That’s one area where you and Accel made a big difference for us, especially in the early days” (on attracting senior executive talent). — Ismail Ahmed, Accel blog interview ²⁹

Mirko Novakovic, Co-founder and CEO, Instana (acquired by IBM) and Dash0:

“The addition of Accel to our existing investor, Target Partners, is another strong endorsement; their guidance and support will be critical as Instana continues to scale, mature and succeed.” — Mirko Novakovic, Target Partners / Instana Series B announcement ³⁰

Hanno Renner, Co-founder and CEO, Personio:

“Adding Accel and Lightspeed Venture Partners, both highly experienced investors, to our list of supporters shows how much people believe in our product.” — Hanno Renner, Personio Series C press release, January 2020 ¹⁹

Connections

• Board member, Celonis — alongside Alexander Rinke, Bastian Nominacher, Martin Klenk (co-founders) ¹⁵
• Board member, Funding Circle (non-executive director) — alongside Samir Desai and co-founders ³¹
• Board member, Miro (from 2020) — alongside Andrey Khusid (CEO/founder) ¹⁸
• Board member, Zepz / WorldRemit — alongside Ismail Ahmed (founder/CEO) ³²
• Board member, Callsign — joined at Series A in July 2017 ¹⁶
• Board member, Carto (CartoDB) — joined at Series B in September 2015 ¹⁴
• Co-investors (frequent): 83North (Celonis), TCV (Zepz), Lightspeed (Personio), Union Square Ventures (Super Payments), Target Partners (Instana)
• Former colleague context: Joined Accel London in 2004 as one of the founding members of the London office, alongside Accel partners who built the European franchise

Sources