Proxima Fusion, Europe’s fastest-growing fusion company and the first-ever spin-out from the Max Planck Institute for Plasma Physics (IPP), is tackling one of the biggest challenges of our time: making fusion energy a reality and designing the first generation of fusion power plants.
With a founding team of researchers and engineers from Max Planck, MIT, and Google X, the company is building the first generation of fusion power plants based on quasi-isodynamic (QI) stellarators – widely regarded as the clearest, most robust path to putting fusion on the grid.
As part of its Series A round, Proxima Fusion chose Roundtable to set up a Luxembourg-based SPV and onboard a global network of strategic angel investors: ex-founders who’ve scaled companies in other industries, industry experts with strong networks, and professionals with experience managing large organizations or significant amounts of capital. To do that, Proxima Fusion needed an efficient SPV structure that would enable them to minimize admin work and keep a clean cap table.
Roundtable delivered exactly that. With simplified investor onboarding, built-in compliance, and automated KYC/KYB, the platform provided an easy way to pool business angels into a single vehicle without losing visibility or adding operational overhead. With this, Roundtable enabled Proxima Fusion to bring in business angels who were already involved with the company and give them a chance to invest in it, building stronger relationships and gaining access to invaluable networks and guidance.
Key takeaways
- Proxima used Roundtable to onboard a global pool of high-profile angel investors – ex-founders and industry leaders with deep expertise and strategic access to valuable networks – while keeping a single line on the cap table.
- Many of Proxima’s angels had already supported the team with key introductions and advice. Bringing them on as investors formalised that support and aligned their interests with the company’s success.
- Roundtable consolidated the SPV setup, compliance, admin, and investor management, facilitating angels’ commitments and giving the team the level of visibility they needed, with real-time status updates.
- The Series A round that the SPV is a part of, is enabling the Proxima Fusion team to concentrate on the company’s next milestones: building critical prototypes, securing resources to push engineering forward, and advancing towards the first generation of commercial stellarators.
Roundtable: Proxima Fusion is a complex and ambitious project and we’re very excited to learn more about it. Could you introduce Proxima Fusion to our readers?
Lennart Bock: Of course. Our official mission statement is a bit technical: We’re building stellarators to power the future, and our vision is Energy for good. By that, we mean enabling human ambitions with fusion energy.
The idea comes from the fact that climate change is one of the biggest risks we face today. We need to transition to renewable energy as fast as possible, but at the same time, global energy demand is still rising. Some industries (and especially heavy manufacturing and AI infrastructure) demand highly dense energy sources, so we need scalable solutions that can deliver clean energy to support industrial growth.
We see two possible futures for humanity: one where we restrict ourselves more and more, or one where we enable prosperity for all countries – and especially those that are not yet well-off. Since energy consumption strongly correlates with wealth, it’s clear we’ll need to produce a lot of clean energy to achieve that.
Our research showed that stellarators hold particular promise for making fusion viable, not just experimentally but as functioning power plants. This led us to spin out from the Max Planck Society: to bring this concept to life as a private company.
The founding team included researchers from Max Planck and MIT, along with engineers. Our first engineer and co-founder, Martin, joined us from Google X.
Our first milestone was to show that stellarators could be developed into fusion power plants. Earlier this year, we published an open-access paper demonstrating that, when scaled correctly in terms of physics and engineering, these devices are feasible. We haven’t solved every single challenge, but we now know there are no fundamental roadblocks towards stellarator-based fusion power plants.
Now our main focus is on the engineering required to make fusion energy a reality.
Roundtable: As part of your Series A round, you set up an SPV through Roundtable. How did you discover the platform, and why did you decide to use it?
Lennart Bock: Correct. We were at a point where we needed to onboard angel investors again. For us, angels bring strategic value: it’s less about the amount invested and more about who the person is, whether they can advise us, and whether we can reach out to them when needed. At the same time, we wanted to keep a clean cap table.
We first heard about Roundtable from our external legal counsel, who had already worked with your platform on other deals. After a few initial calls with the team, it was clear to us that the platform was a very good fit: it was straightforward to use, cost-effective, and offered a very smooth user experience.
One feature I particularly liked was the visibility into the investor progress. With other providers, everything may be taken off your plate, but then you’re left in the dark wondering: What’s the status? How are we doing? Roundtable gives you a birdseye overview, which we found very useful.
The onboarding process was smooth for us and for our business angels. A big advantage is that we don’t have to worry about KYC or KYB – whether someone invests as an individual or through an entity, Roundtable manages it all, which makes the entire process much simpler.
Roundtable: Can you tell me more about the process of setting up an SPV with Roundtable?
Lennart Bock: When setting up an SPV, you can choose between two models. The first one is the “founder-led model,” where you, as the founder, act as the manager of the vehicle; this also means you have to deal with all the internal administration of that vehicle.
There’s a second option, which we ended up choosing, and which is to let Roundtable manage the investor pool. We still get a power of attorney (POA) in the end, but they handle everything else: agreements inside the pool, gathering additional information when needed, and managing compliance. We just get the POA to execute transactions, but the operational and compliance work is off our plate.
Essentially, Roundtable handled everything, from setting up the SPV to opening a bank account. That entity now sits on our cap table, and the investors who came in through it are our angel investors.
The SPV was structured as a Luxembourg SCSP, which is generally convenient in Europe and worked well for our angels. Its main advantage is the transparency, which makes it easier to comply with anti-money laundering rules and with KYC/KYB requirements for future fundraising rounds. At the same time, angel investors in the vehicle don’t have to be overly visible to the outside if they prefer not to be.
Roundtable: How long did the whole process take, from beginning to end?
Lennart Bock: For us, it took roughly three months, but not because of Roundtable. We were still in the process of bringing in additional angels, which stretched things out.
The process with Roundtable can actually be very fast. If all angel investors are ready, I’d say it could take a week or two (at most). You invite everyone, they complete their KYC – which usually takes a day or two – and once everyone is in, they sign the LPA. Things move forward very quickly.
Roundtable: Speaking of angel investors, can you tell me a bit more about yours? What’s their typical profile?
Lennart Bock: When we choose angel investors, we look for people who can really support us on our journey. Since there isn’t yet a “successful fusion company” model to follow, we look across different dimensions: ex-founders who’ve scaled companies in other industries, people with strong networks we might need access to, or those with experience managing large organisations or significant amounts of capital.
Many of them had already helped us by making introductions and taking calls when we needed advice. Bringing them on as investors is also a way of rewarding them and formalising that support. The strategic idea is that if people are part of your journey, they’re more willing to help you.
There’s a general principle here: if you want advice from high-profile people, instead of paying them as advisors, you should give them a chance to invest. That way, they have a direct interest in your success. Essentially, when those people are on your cap table, it’s easier to ask for introductions, industry insights, or specific knowledge, because you already have an ongoing relationship with them.
Roundtable: That’s very insightful. Did Roundtable facilitate raising funds internationally?
Lennart Bock: Yes, Roundtable helped with that. There are some restrictions, not because of the platform, but due to compliance and reporting rules in different countries, for example in the US.
The team was very proactive and accommodating in handling all that and facilitating our exchanges with investors, so that we could forward all relevant information to them and speed up reporting for them.
Overall, the team was always very helpful and responsive. Whenever we needed something specific, they were ready to brainstorm with us and accommodate our needs, which has been a very positive experience.
Roundtable: How was your experience with the platform?
Lennart Bock: The platform is excellent. I can just log in, accept commitments, and see a quick status overview. I really value being able to track everything in real time.
Roundtable: How would you sum up the operational benefits of using Roundtable?
Lennart Bock: Roundtable makes it much easier to get approval from a large number of investors. There's just one entity on the cap table, and that’s a huge operational benefit. Plus, compared to other SPV setups, Roundtable was definitely more affordable.
Another plus was that we didn’t have to manage the vehicle ourselves afterwards. At the end of the day, an angel pool (at least at our size) isn’t meant to be heavy on decision-making. Investors participate, but you don’t want the operational overhead of managing that yourself.
In short, for pooling angel investors, Roundtable is an excellent choice, and I’d definitely consider using it again.
Roundtable: What’s the impact that this funding round will have on Proxima Fusion?
Lennart Bock: The Series A round, including the SPV, allows us to move into real engineering and hardware development. We’re now building prototypes of different subsystems, especially a large magnet typical for the kind of fusion demonstrators we need. The funding ensures we can build those prototypes, cover procurement, and pay our people.
As for Roundtable’s SPV, its main strategic benefit is the advice we’re getting from our business angels and the access to their networks, which is invaluable.
Roundtable: Last question, what advice would you give to other founders of tech startups looking to raise funds?
Lennart Bock: Build trust before you need it. That’s the most important thing. Build trust with investors and partners early, so that when you actually need it, the trust is already there.
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