Bridging the gap between accounting requirements and the daily decisions of a business owner is how Mark O’Reilly helps clients move forward with confidence.

Mark O’Reilly is a partner at Walter Shuffain providing tax and assurance services to closely held businesses and their owners. He is known for bringing a practical, business-minded perspective to his work, using financial information not only to meet compliance requirements but also to help clients better understand their operations, manage risk, and identify opportunities that support profitability and long-term growth.

Mark began his public accounting career at a regional firm in Randolph, Massachusetts, where his early work was primarily focused on audits. The firm specialized in healthcare, giving Mark a strong foundation in audit services and valuable insight into the operational challenges faced by healthcare organizations. He later joined Richardson and Company after recognizing an opportunity to build long-term client relationships within an advisory-focused firm environment—one that allowed him to combine deep technical expertise with a broader, consultative approach.

As an advisor to business owners, Mark helps evaluate financial decisions that affect both the business and its owners. Clients rely on Mark not only for accurate reporting, but also for perspective on how financial choices today influence future flexibility and value.

Mark’s work with privately held businesses spans various industries, including construction, manufacturing, real estate, professional services, and wholesale and distribution. His experience across these industries allows him to identify trends and opportunities that may not be visible in day-to-day operations. He is particularly effective at helping clients understand how small changes in margins, pricing, or processes can lead to meaningful financial results over time.

Mark’s client approach begins with listening. He takes a holistic view of each engagement, using compliance work as a foundation for broader conversations about improvement and growth. Rather than allowing tax considerations to drive decisions in isolation, Mark helps clients evaluate how strategic choices impact the business as a whole and align with long-term objectives.

Mark is a member of the American Institute of Certified Public Accountants and the Massachusetts Society of CPAs. He is also involved in the finance committee of his church.