From Problem to Proof Yumi Tsoy on what founders really need before raising capital

As Partner at Bethnal Green Ventures, (BGV) Yumi Tsoy backs start-ups that don't just scale - they solve. She shares what early-stage founders must get right before pitching investors, how to turn a "no" into a future "yes," and why lasting impact always beats the latest trend. Tsoy leads investment selection for BGV's Tech for Good programme, works closely with founders on building and growing their start-ups, and oversees impact management across all funds.

Tsoy knows what it takes to build a world-changing company and how to spot one early. Whether it's helping a founder sharpen their value proposition or guiding teams through BGV's Tech for Good programme, she brings clarity, conviction, and a deep belief in the power of tech to drive lasting impact. In this conversation, she breaks down what founders should focus on before raising their first round, how to navigate investor rejection with resilience, and the start-up trends that truly matter - not just now, but for the long haul.

What are the top three things founders should focus on when preparing to raise their first round of funding?
First, you need a deep understanding of the problem. How big is it? How important is it? The strongest founders don't rely on assumptions; they articulate the problem clearly and stay in constant conversation with their audience – testing, learning, and refining –to ensure they deliver the most effective solution.

Second, you should be able to explain your solution clearly: how it works and why it's stronger than anything else already out there. Building a venture is never simple, but being upfront about your unique edge makes it easier for both you and your investors to weigh the risks and get excited about the opportunity.

Finally, collect whatever evidence you can that people want what you're building. In the early days, you may not have vast amounts of data or traction, but even small signals from user research, a first MVP, quick tests, or early signs of demand can go a long way. They show your idea isn't just a side project, but the beginning of a product that could reach millions.

When evaluating early-stage start-ups, what key factors do you prioritize?
As a tech for good VC, we look for ventures that build impact into their business model from day one. In practice, that means positive social or environmental outcomes aren't just a by-product; they sit at the core of commercial success. The more the company grows, the greater its impact.

Once a venture passes this first screen, we look for teams with a unique insight into a major unsolved problem and the resilience, ambition, and skill to tackle it. A good example is our portfolio company Vouchsafe, which built an inclusive identity verification technology that helps organisations serve the one billion people without government-recognised IDs, opening access to vital services, such as healthcare and banking.

How should founders handle a "no" from an investor? What's the best way to build long-term relationships, even if they don't secure investment straight away?
It might sound cliché, but every "no" is a chance to learn. If it comes early, your venture likely didn't pass the initial screen. If it comes after several conversations, there might be something else at play, so be sure to ask for feedback and apply what you can. It's worth remembering rejection isn't always about the strength of your venture; sometimes it's simply not the right investor fit. Instead of forcing a relationship, focus on finding value-aligned investors who share your vision and have the expertise to help you grow.

What start-up sector or trend excites you the most at the moment, and why?
Trends tend to be fleeting by nature, so I prefer focusing on ventures addressing needs rather than short-term 'wants'. At BGV, this means supporting companies that tackle healthcare, climate, and social inequality–challenges where lasting change, deep impact, and commercial opportunity go hand in hand.

Which three start-ups that you funded this year excite you the most - and why?
It's a tough choice because we've invested in over 20 ventures this year! If I had to narrow it down, I'd highlight one from our three investment themes: a sustainable planet, an inclusive society, and healthy lives. They're all driving meaningful change in their fields and are absolutely worth watching.

Windfall Energy developed an affordable, portable battery that reduces energy costs for the millions of households currently excluded from the clean energy transition. At scale, their solution could facilitate a significant increase in the proportion of renewable energy used by the grid.

Fosterli is reimagining the fostering system, using technology to streamline applications and recruit more carers. The potential here is enormous–not only in improving the experience for foster carers, but also in helping more vulnerable children find homes.

Breath Predict has developed an innovative technology that can predict asthma attacks up to 3 days in advance. It's a brilliant example of how tech can make healthcare more proactive and preventative.