Jonni Leporanta: The Story of Grant Thornton
Henri Putkonen
This article is published in partnership with Grant Thornton Finland.
Grant Thornton Finland’s story begins in a peculiar place: a handshake in the legendary Marski nightclub in December 1992. What started as an entrepreneurial initiative between two founders has, over three decades, grown into a nationwide advisory firm with more than 80 professionals. Alongside that growth is the career of Jonni Leporanta, today the Managing Partner, whose journey mirrors the evolution of the firm.
Entrepreneurial Beginnings
The Finnish firm officially began operations in January 1993 when two partners, Mårten Fors, whose background lay in regulatory-driven accounting services, and Joakim Rehn, who brought with him a loyal base of Finnish family-business clients, decided to join forces.
Shortly after the firm’s founding, the partners received an unexpected call from London. Grant Thornton International was advising a major merger in Finland and needed a local partner capable of handling both the local language and English professionally. For a young Finnish firm, this was a crucial opportunity.
With digital tools still years away, the transaction became a test of confidentiality. “All the confidential documents were locked in one room. The target company’s personnel worked from eight to five, and we came in afterwards, working until 6 am,” Rehn recalls in the firm’s 30-year anniversary video. The successful transaction ultimately helped fund the firm’s earliest years and laid the foundation for future partnership.
Through the late 1990s and early 2000s, Grant Thornton Finland expanded steadily: first into tax advisory in 1995, then into Nordic collaboration in 1996, and later into new regional offices in Tampere and Turku.
Introducing Jonni Leporanta
Amid this period of expansion, Jonni Leporanta joined Grant Thornton. Having begun his studies at Hanken School of Economics in 1995, he gravitated toward accounting for its concrete nature. Growing up close to a small family business in the horology industry, he found himself naturally drawn to understanding how companies operate. “Being able to understand various kinds of companies and connecting the actual business with the financial reporting were factors that appealed in auditing,” Leporanta remarks.
After interviews with both founders, Leporanta joined Grant Thornton in 2001 as an Audit Junior. Early on, he found himself working on a major cross-border project between a large U.S. client and a Finnish company. “I had barely joined when I was pulled into a large transaction. I still remember sending documents to a U.S. law firm by fax, right before Midsummer. Friends had started grilling, and we were still fighting with the fax machine,” he laughs.
Those early years exposed him to a combination of audit work and ad hoc deal-related tasks. After completing his KHT (Authorised Public Accountant) qualification three years later, he began building his own client portfolio.
Jonni Leporanta
At a Crossroads
Grant Thornton’s Finnish practice did not yet have an established transaction advisory team, and Leporanta found himself contributing to several due diligence assignments alongside his audit responsibilities. Eventually, he reached a point of decision. “I noticed that if I truly wanted to succeed and thrive in either service, I had to choose one to put all my focus into.” In 2007, at the dawn of the financial crisis, Leporanta chose transaction advisory as a partner.
The shift brought a new dimension to his work. “Becoming a partner meant building networks, working more closely with external stakeholders, and marketing Grant Thornton’s brand. Transaction services are sensitive to economic cycles, so client acquisition changes with the market. I appreciated the challenge. It brought new motivation every day.”
Leporanta emphasizes that the partner role is not set in stone and is adjusted to best fit the person in question. “Some people are advanced in some avenue of technical skills; some people are more sales oriented. The position adjusts to each person’s strengths.”
In 2012, he became Head of Transaction Advisory, gaining his first boardroom experience and deepening his leadership responsibilities.
Stepping Into Executive Leadership
Being promoted to head of transaction advisory in 2012, Leporanta got to experience working with the leadership team, proving to be useful leading into his managing partner position promotion in 2020. “Moving into the CEO role was a significant change. Suddenly, I became more visible to both our local employees and the global GT network,” he says. Moreover, now instead of just attending the leadership meetings, Leporanta’s task was to lead them.
Leporanta believes that his experience in both auditing and transaction advisory played a significant role in his eventual nomination as CEO. “Knowing these two businesses inside out meant I understood two pieces of the puzzle,” he reflects. Furthermore, Leporanta emphasizes that communication skills are important for CEOs. “As a managing partner, you are lonely with some decisions,” Leporanta notes. “Even though I’ve built a strong Nordic network after stepping into the role, something I didn’t anticipate, the responsibility still rests with you.”
Having held leadership positions since 2007, Leporanta highlights the importance of being present. “I strive to always be available for my team. You can never communicate too much.” Considering whether the leadership style has changed, Leporanta responds with a grin: “Definitely – or at least hopefully. During my leadership positions, I’ve also had children, which teaches many of us a great deal as humans.”
Grant Thornton Finland’s key client focus remains on serving dynamic mid-market clients, a segment Leporanta believes offers both dynamism and growth potential. “You must find your place in the market. Understanding your strengths and competing on them is key,” he notes. Mid-market clients, often with international operations, he argues, allow the firm to differentiate itself: “It’s a fascinating segment. Clients are active, ambitious, and constantly evolving.” At the same time, he emphasizes that a healthy professional services market includes firms of many sizes with different service offerings. “That variety benefits clients and strengthens the industry.”
25 Years at Grant Thornton
Celebrating 25 years at Grant Thornton, Leporanta reflects on what has kept him there. “It’s the variety. The clients. The colleagues with a ‘let’s do it’ attitude. I’ve had the opportunity to work in very different roles while staying under the same flag.” Watching the firm grow year after year has remained a source of motivation.
Certain moments have stayed with him. He recalls one particularly difficult M&A assignment where the timeline was tight and the circumstances challenging. “There was a young lawyer at the buy-side law firm who handled the challenging situation with such positivity and drive. That attitude changed the whole dynamic. We focused on finding the best solution possible. It really taught me how important mental attitude is. No one needs advisory services if everything was easy.”
To our younger readers, Leporanta encourages being curious and trying diverse career paths. “If you’re considering starting your career auditing, it is a good choice. During my initial years, I learned crucial skills in financial reporting and reading financial statements. These skills have proved to be especially useful in transaction services.”
The managing director ends with one last piece of concluding advice: “There are so many possibilities within the industry. You have time to specialize down the road. Being curious, having fire in your belly, and wanting to learn takes you far.”
Henri Putkonen is the Editor-in-Chief of AFA Quarterly.