Nadia Sergejuk
Co-Founder & COO at Lagoon
Nadia, you spent years working in legal and institutional finance before moving into blockchain. Could you share what first sparked your interest in the space, and what differences between traditional finance and digital assets surprised you the most?
My interest in the space was first sparked during a seminar at Norton Rose Fulbright overlooking the Tower of London back in 2015. I remember the day vividly, as this office has an absolutely stunning view of the City of London. There was a session on programmable agreements and the potential effects of this new technology on the financial and legal sectors.
Fast forward to 2020, I was working as an investor in the deep tech corporate venture arm of a large conglomerate when I started seeing more and more applications being built on top of blockchains. This was the moment I realised the impact the technology could have on how we operate and transact. Right then, I knew that blockchain was a technological frontier I absolutely wanted to engage with and build in.
When I entered the space full-time in 2021, what surprised me the most was the culture. The ecosystem was open, welcoming, and entirely lacking the established hierarchies and rigid structures you often see in traditional industries. Experimentation, innovation, and optimism defined the space in 2021, and everyone was welcome to join. On the flip side, I was also surprised by how technologists and engineers building in the sphere had a very vague understanding of traditional financial industries.
It took six years from the first spark to going all in, which makes it feel like anything but an impulsive decision. Your career also spans investment management, venture capital and startups. How has that experience shaped the way you approach building your own company today?
I am certain that having sat on both sides of the table gives me a unique advantage. Firstly, it gives me a network and an understanding of what it takes to be a builder and venture investor. After all, the network is key whether you’re a founder or an investor.
In my work as a venture investor, I had to analyse early-stage companies and sectors while they were still in their infancy. I had to assess teams and put a price tag on their future success. Most importantly, in my view, I gained an insider understanding of how venture capital works with all its nuances, the good, the bad and the truthful, as I’ve seen it from both deep tech and fintech perspectives. Moreover, I got a clear understanding of why many funds fail to raise their second or third fund. It’s just a numbers game, so as a founder, you can often do everything right but still struggle to raise your venture round.
Also, most VC funds need to raise external capital and are very familiar with the fundraising process. Market cycles and external factors all play a role for both funders and investors. Now, I build with a clear-eyed realism about macro environments and focus on the fundamentals to be less dependent on the constantly changing market winds.
Regarding investment management, it is a vast universe. You can be an incredibly sharp tech investor but not know where to start with real estate. I have crossed different verticals and feel there is still so much more to learn. There is no doubt in my mind that being on the investor side taught me to navigate the complexities of scaling a business much more effectively.
Ultimately, I see this as a circular journey: you invest, you build, you exit, and so eventually, you return to investing. Right now, I am focused on and incredibly energised by the building phase.
This “circular journey” framing nicely captures the back-and-forth between investing and founding. Your company, Lagoon, scaled to hundreds of millions in TVL in its first year, and you're building it with a co-founder. What changed most about your role as a leader during that growth, and what have you learned about making the partnership work?
We are fortunate that we never really had to grow our headcount significantly to achieve this scale. We are still largely the same dream team that started almost two years ago. Of course, the company has had people come and go during this time, but the core has remained intact. The key to this growth has been building with scalability in mind from day one, which means that the capacity of our technology should be independent of human headcount.
However, as we continue to scale, my focus as a leader is shifting. We are spending more time on institutional client-facing initiatives, regulatory, and brand-building. Being past the MVP stage, Lagoon is a scale-up now, and we are bringing in different people and specialised skill sets to help us navigate this next growth phase.
None of this would have been possible without the right partnership at the core. As a matter of fact, complementary skillsets and emotional maturity are key.
It's notable that as Lagoon scales, your own focus is switching toward regulatory and institutional priorities, which ties directly into your background in law, risk, and governance. What advice would you give founders in blockchain on how to balance speed with building sustainably?
Speed and sustainability aren't opposites — treat them as if they are, and you’ll build something that collapses under its first real durability test. The way around that trade-off is to build for scale from day one.
Understand risk management and regulatory frameworks that affect your business, because in this industry, they are foundational from a company’s earliest days. I think these factors are now defining for the next generation of businesses built on blockchain.
As for my legal background, it just means I default to asking what could go wrong before asking what could go right, and founders who build with that same discipline usually grow faster in the long run.
You’ve spoken about building companies for the next generation. To close, let’s turn to the person who helped shape your own path. When you were building your career, was there a female role model you particularly looked up to?
My mum has been my greatest role model when it comes to career building, people leadership, and professional development. She taught me how to take on calculated risks, believe in myself, and pursue my dreams no matter what direction they are in.
She also showed me how to be independent and self-reliant, while still being able to ask for help, surround myself with great colleagues, and take people on a journey. Despite her being in a completely different field, seeing her build a career and family with passion, perseverance, hard work, and a lot of energy has been defining for how I approach my own life and professional journey.
