Experience You Can Trust. Advice You Can Act On.
An independent firm of Chartered Certified Accountants based in East Sussex, working with owner-managed businesses, entrepreneurs, family companies and private clients.
Founded by Mark Underdown FCCA
Founded by Mark Underdown FCCA, the firm is built upon more than 20 years of professional practice experience and over a decade of leadership as a director within a well-established chartered accountancy firm. Mark is Director and Founder of MSU Advisory Limited.
We believe that modern accountancy should go beyond preparing accounts and filing tax returns. Our role is to help clients understand their numbers, plan ahead, manage risk and make better-informed decisions. Whether you need reliable compliance support, proactive tax planning, outsourced finance director expertise or practical business advice, we provide guidance that is commercially relevant and easy to understand.
How we work
Our approach is built on long-term relationships. We take the time to understand your business, your ambitions and the challenges you face, so that our advice is tailored, timely and genuinely useful. By combining traditional professional standards with modern systems, cloud technology and automation, we help clients build stronger, more efficient and more resilient businesses.