In this How I Invest, we speak to Joost Kruytzer of BigCircle Ventures: an experienced entrepreneur and venture builder committed to accelerating technological solutions in climate and circularity.
With a background in physics and years of experience in consulting and the startup world, Kruytzer co-founded BigCircle together with three co-founders. Their mission: to turn groundbreaking innovations from laboratories into impactful startups. In this interview, he shares what drives him, the unique venture building model of BigCircle, and why now is the time for investors to step into deep tech for a more sustainable future.
Let’s start with your background, your passion, and why you started BigCircle…
“I was trained as a theoretical physicist, but I quickly discovered that I enjoyed setting up new initiatives with teams much more. That’s why I moved into consultancy after my studies, where I worked for over twenty years. After an initial period, I went to London during the dot-com boom to establish a new consultancy firm. Then came my first step toward impact: I spent two years as a volunteer supporting local NGOs in Sri Lanka. Back in the Netherlands, I focused on healthcare consulting and helped a small firm grow, eventually becoming active internationally through KPMG.”
When did startups come into view?
“A few years later, as a partner, I left consultancy for the startup world. I saw how crucial technology is for keeping healthcare accessible—both here and in emerging markets. That’s how I met the founder of NLC, the healthcare venture builder. Starting in 2016, I worked as COO to help build the model and scale the organization. After launching one hundred startups, I realized that this venture-building model is just as needed in other sectors. I dove into climate and circularity—challenging domains full of underused technologies. That’s how BigCircle was born.”
What specifically motivated you?
“My motivation is twofold: solving big societal challenges and the joy of creating something new with a team. I started BigCircle together with three co-founders—experts in climate and circularity—to combine their deep knowledge with my venture-building experience. We now have a team of nine, collaborate with nearly all Dutch universities, and are launching our first ventures. Next year we’ll expand the team and start international collaborations with universities.”
Why focus specifically on deep tech in climate and circularity?
“Because these are major societal challenges where technology plays a crucial role. Europe develops a lot of innovation, but much of it stays on the shelf. We bring that technology—often still in the lab—to market. Think of greening the steel industry, the next generation of solar panels, or plastic recycling. These are high-impact solutions, but they require long development timelines. Our venture-building model speeds up the process and improves the success rate.”
Why choose venture building instead of just investing?
“At our core, we are not investors—though we do provide seed funding. Our main activity is creating new startups. We work with universities and their scientific teams to identify inventions that have been left behind for the wrong reasons. That often happens because researchers want to keep researching and don’t take on the entrepreneurial side.”
Don’t universities already have people for that?
“Universities do have Tech Transfer Officers (TTOs) who help scientists commercialize their inventions. But they have limited capacity and can’t handle all innovations. That’s where we come in. We analyze the potential, just like an investor would, and only select technologies with real investment potential. When we find something promising, we sign a license agreement with the university, establish a new legal entity, and recruit a founding team. Usually, that’s one or two people who become the startup’s CEO/CTO, alongside us as co-founders.”
How do you find the right people to lead such startups?
“Through our network, recruiters, and lots of conversations. We look for entrepreneurs who can engage with universities but are also market-savvy. Scientists often stay involved, but others take the lead in running the startups. Our role then shifts to that of active shareholder—we support with financing, legal structure, and go-to-market strategy.”
What are the investment opportunities for investors?
“There are three ways to invest with us. The first is through the venture builder itself: this is the earliest stage, with the highest risks but also the greatest potential returns. Because we build dozens of startups, we offer immediate risk diversification. This model appeals to angel investors who want to stay close to the action.
The second route is via our closed-end fund. You enter a bit later, once the ventures are established. It’s still early-stage, but with a slightly more conventional structure. This fund will eventually include about thirty ventures, offering broad diversification.
Finally, there’s the option to invest directly in individual ventures. Some investors come in via the builder or the fund to stay close to the pipeline and later actively engage in a specific startup.
At this moment, an investment round is open for the venture builder. Interested parties can reach me via our website (bigcircle.ventures).”
Do you also work with existing startups?
“No, our model is really focused on technology that’s still on the shelf at universities or companies. If a startup is stuck but holds valuable IP, we might explore taking that on. But we are not an accelerator for existing teams.”
Why are these themes particularly attractive for investors right now?
“Climate and circularity are not only impact topics—they’re economically strategic. Europe wants to become independent in energy and raw materials. That requires technological innovation, which is exactly where we operate. Large markets, strong policy momentum, geopolitical urgency, and industrial demand come together here. Impact and return go hand in hand.”
Do you receive government support or want to remain independent?
“Both. Government subsidies help with early-stage technological development, but we want to avoid overdependence on political fluctuations or restrictive terms. Our goal is to make that very first phase investable so more private capital can flow in.”
How do you reduce risk for investors?
“First, we improve the success rate of each startup by selecting high-potential technologies, assembling strong founding teams, and providing intensive support. Building dozens of startups also helps us accumulate knowledge, networks, and strong in-house capabilities.
Second, investors can get involved through our structures without bearing the extreme risk of a single deep-tech startup. By bundling dozens of ventures in one model or through a diversified fund, we reduce risk and make it more attractive to both institutional and angel investors.”
Do investors need to be prepared for dilution?
“Yes, but that’s generally a good sign—it means there’s enough capital coming in to bring the technology to market. Some ventures need less capital, others more, but by clearly mapping the financing roadmap from the beginning, we ensure they connect with the right funders in time.”
How is your portfolio doing after the first year?
“Since last summer, we’ve been working with fifteen Dutch universities and research institutions. We now have four pilot projects underway, including a publicly announced one with Utrecht University for next-generation plastic recycling. We’re on schedule: on average, it takes about a year from the first lab proof to launching a startup.”
Why is now the right time to get involved?
“As I said: Europe wants to become energy and materials independent and compete through innovation. So political and economic necessity are converging. Deep tech in climate and circularity is receiving strong, long-term momentum. ‘Never waste a good crisis’: start building now to capture strategic markets in the long run.”