dmg media Ireland has selected 40 brilliant young minds in the accountancy industry as part of the 40 Under 40 series

James Peyton - Senior Manager, RSM Ireland

James Peyton is a Senior Manager in the Corporate Finance department at RSM Ireland, with over a decade of experience.

He specialises in M&A, due diligence, valuations, and fundraising. Over the past three years, Peyton has been a key contributor to the department’s strong growth.

Peyton works with clients across a broad range of sectors, including business services, logistics, construction, SaaS, technology, and engineering.

He takes pride in RSM’s proactive approach, delivering high-quality, value-driven advice that consistently earns the confidence and referrals of clients.

His route into corporate finance was shaped by a strong foundation in audit, tax, and restructuring. Having trained with DHKN in Galway, Peyton gained early exposure to audit and tax before moving to Joe Walsh Accountants in Dublin, where he helped to establish the accounts department.

His role quickly expanded into insolvency, restructuring, and corporate finance, advising businesses across a range of sectors.

Those experiences, often in high-pressure situations, gave Peyton a deep appreciation for finding solutions in difficult scenarios and honed the project management skills he now brings to complex transactions.

What motivates Peyton most is the people behind the businesses he advises. He thrives on meeting entrepreneurs, hearing their stories, and guiding them through defining moments, whether raising capital to grow, pursuing growth by acquisition or achieving the right exit.

Just as importantly, he is passionate about the continued growth of RSMs corporate finance offering, fostering collaboration across the firm’s service lines, and strengthening its sectoral expertise, particularly in technology.

For Peyton, success is about more than transactions; it’s about creating a culture of trust, collaboration and growth, for the firm and its clients.

• Hobbies: "I have a passion for travel and exploring new cultures, which often means seeking out local food experiences wherever I go."
• Best Advice Ever Received: "When I asked a former mentor how to reach the top, he gave me unexpected advice: go travel, meet people, and explore the world. He said the knowledge and skills would come in time, but what would truly set me apart is becoming more personable and understanding different perspectives.
• Why I love my job: I love being around smart, driven people. We spend so much of our lives at work, and for me, time not spent learning and developing is time wasted.
• Motto for life: “Waste no more time arguing about what a good man should be. Be one.” – Marcus Aurelius. For me, it’s a reminder that actions speak louder than words. In business, as in life, integrity, consistency and follow-through matter far more than talk.

Simon Rattigan - Director, RSM Ireland

Rattigan is a Director in RSM Ireland's Forensic and Investigation Services practice.

He provides specialist forensic services including accounting support for commercial disputes, and investigation into fraudulent accounting, misconduct and financial issues.

Rattigan joined RSM in 2024 and prior to that spent 14 years at a Big 4 firm.

He has provided expert opinion on matters of quantum for various commercial disputes, post-acquisition disputes, and independent expert determinations, and he is skilled at producing clear and articulate analysis in complex situations.

He is a Business and Economics graduate from Trinity College Dublin and earned a Postgraduate Diploma in Accounting with Distinction. He is also a Fellow of Chartered Accountants (CAI) and a Certified Fraud Examiner (CFE).

Rattigan is passionate about leading high performing teams and likes to roll up his sleeves and lead by example. He enjoys working in a flat structure, putting quality work at the forefront, and empowering those around him to succeed.

Being part of such a dynamic firm and thriving practice area is big motivating factor going to work every day. He lives with his wife Sarah, and daughter Marianne, so there is no shortage of motivation outside of work either.

• Hobbies: I like to be as active as possible, whether that’s playing golf, going to the gym, sailing, or just going for a run to clear my head. I’m also a music lover, a bookworm, and enjoy playing snooker, so I can be just as content being ‘inactive’. Admittedly these hobbies have taken a back seat of late to toddler-based activities.
• Best piece of advice ever received: Early in my career I was advised by a mentor to be genuine at all costs, don’t pretend to know more than you do, and never try to ‘up sell’ clients. I have carried this advice with me and always focused on building relationships based on trust and sincerity.
• Why you love your job: I love the variety – no one day is the same and no client issue is the same. I typically work with clients that are in difficult or distressed scenario, so it gives me a strong sense of purpose to help them navigate challenging situations. I also get energy from working with great people, which I am fortunately surrounded by.
• Motto for life: “Without friction there is no growth”. I generally find being on the edge of my comfort zone the most rewarding, which I think applies in both professional and personal contexts