Harrison Wittenberg
Full name: Harrison Wittenberg
Job Title: Senior Manager – Renewable Energy Tax at STX
Location: New York
Nationality: American
Years at STX: 3+ years
1. You joined STX in its early U.S. days and helped build what became the US Strive by STX team. What drew you to take that leap and what do you remember most from those early-building years?
When I joined, STX was just starting to establish itself in the U.S., with only around 15 or 16 people in total. What drew me in was the chance to build something from the ground up in a market that was evolving rapidly.
Those early years were all about firsts: first meeting, first contract, first transaction, first everything. Working in a crowded office space with one meeting room, you could hear everything. And while it was a bit hectic to start, that was the best way to learn. Every individual win really felt like a team success.
It was also my first real exposure to cultivating client relationships end-to-end, from cold outreach to building trust and ultimately executing transactions together. I built a large client base early on, several of which I still work with today.
Those years taught me two important lessons: you must move fast when opportunity hits and always lead with value. That mindset laid the foundation for everything we’ve built since in the US—Strive, the Tax Credit desk and the broader STX platform in the U.S.
2. What drew you to build out the US Tax Credit desk, seemingly an entirely new market?
The intersection of finance, strategy and clean energy is where I like to operate and this market was exactly that.
When the Inflation Reduction Act (IRA) passed, it was clear that STX was uniquely positioned. We already worked with hundreds of renewable energy developers and maintained long-term partnerships across technologies like wind, solar and RNG. Rigorous due diligence and risk evaluation were and still are part of our DNA. On the corporate side, we had an active client base allocating capital to decarbonization. The emergence of transferable tax credits created a rare win-win: a simple, scalable way to save millions in taxes while directly supporting the energy transition.
3. What makes a successful corporate buyer in the tax credit market?
In one word: readiness. Success in this market isn’t just about identifying a good opportunity — it’s about being commercially prepared to capitalize when it presents itself. That means aligning tax, treasury, legal and the C-suite. It means having a clear framework, establishing an internal deal team and partnering with experts who can execute. This market rewards decisiveness and preparation.
That’s where we come in: helping buyers not just identify value but capture it.
I have a lot of respect for the tax professionals who step up and drive these transactions forward. It’s rare to see a handful of individuals generate this level of value for their organizations—delivering millions in savings while directly advancing the U.S. energy transition.
4. What did it take to build STX’s tax credit desk from the ground up?
Markets move fast, but fundamentals don’t. Building a desk isn’t about one great idea, it’s about building the team, the strategy and the infrastructure to deliver again and again.
When the IRA passed, I was managing over 80 clients while helping lead our Strive platform. I saw tax credits as a scalable bridge between developers needing capital and corporates seeking tax savings. We were well-positioned, but it required a completely new playbook.
I built the strategy, sourced early relationships and educated both sides of the market. We earned trust with clients by leading with transparency, staying ahead of market shifts and solving real problems. Growth came from execution and from consistently earning the next opportunity.
I’ve been fortunate to help build two desks at STX, both anchored in the same belief: with the right structure, deep expertise, trust, and timing, you can unlock new markets that create value for everyone involved.
5. You are the deal maker of STX’s record high US$1 billion tax credit transfer, one of the largest known credit transfers under the IRA to date. How did it come into being and what key ingredients made this transaction successful?
When both sides treat the process as a strategic partnership and not just a one-off transaction, you create the foundation for repeatable success. That shared vision is what allowed us to break ground in a market-defining deal.
It took a lot of structuring and problem-solving across the Legal, Finance and Regulatory teams. It didn’t happen overnight—it was the result of months of coordination and staying focused on the bigger picture.
From the developer’s perspective, trust and patience were everything. These transactions are new, complex and carry real risk. They came in with thorough diligence and clearly laid out how the moving parts fit together—making it easy for all parties to engage with confidence. The buyer came in commercially prepared—with internal alignment, sharp risk evaluation and the willingness to lead. It wasn’t easy, but those are the deals worth doing.
That level of collaboration is what will define the next wave of growth.
6. Looking ahead, how will the transferable tax credit market evolve?
There’s definitely a lot of uncertainty right now, as we’re in the early stages. The next phase will be defined by buyers who approach this as a portfolio strategy rather than a one-off win. We’ll see greater credit differentiation, improved price discovery and sharper risk allocation. On the developer side, the winners will be the ones who treat credit sales as a repeatable commercial channel, not just a one-time liquidity event.
Finally, intermediaries will need to do more than matchmake—we must structure, guide and deliver certainty in a market that still lacks standardization. That’s exactly where we’ve built our edge.
7. What’s been most rewarding for you in building these markets?
Without question—it’s the relationships. I’ve built genuine friendships through this work. You spend months with people navigating complexity, solving problems, earning trust. That bonds you. The market may be transactional, but success is always relational. That’s what makes it fun.
This market rewards creativity — creating partnerships, developing new strategies and advancing structures that set the foundation for long-term commercial success. Helping a client save US$30 million while funding a clean energy project? That’s real, tangible impact.
And of course, I still love the moment when the deal finally comes together—when all the moving parts click into place and you execute something that looked impossible a few months earlier. That feeling never gets old.