Our Firm

Lanphier LLP is a full-service CPA firm in Denver, Colorado. Established in 2009, we provide tax, accounting, advisory, and legal services to businesses and individuals across the United States and around the world. Our firm was built on a simple idea: that clients deserve the caliber of expertise found at the largest national firms, delivered with the personal attention and genuine relationships that only a boutique practice can offer.

We were founded by Brittany and Dennis Lanphier, a husband-and-wife team who met while working in the international tax group at Deloitte, one of the Big 4 accounting firms. After years of serving multinational corporations and high-net-worth individuals at that level, they saw an opportunity to bring that same depth of knowledge to a practice where every client would feel like the only client. That founding vision continues to drive everything we do.

From Two to Twelve

What started as a two-person firm has grown into a team of twelve professionals spanning tax, accounting, advisory, and client services. Our team includes CPAs, Enrolled Agents, a tax attorney, and specialists with backgrounds ranging from Big 4 public accounting to corporate finance, forensic accounting, and even the music industry. This diversity of experience gives us the ability to serve clients with wide-ranging and often complex needs.

Nationally Recognized

Over the years, Lanphier LLP has earned national recognition for our thought leadership, innovative processes, and commitment to the advisory model of public accounting. Our partners are sought-after speakers at national conferences and have built a reputation for pushing the profession forward. We have been recognized for our pioneering work in client onboarding, tax advisory workflows, and the use of technology to deliver more proactive, planning-oriented services.

A Global Reach

While we are based in Denver, our reach extends far beyond Colorado. We serve more than 500 clients across the country and around the world. We have filed US tax returns for businesses and individuals on every continent -- including Antarctica. Whether you are a Denver business owner, a US expatriate living abroad, or a foreign national with US tax obligations, we have the expertise and infrastructure to serve you seamlessly.

Our Values

At the heart of our practice is a commitment to building lasting relationships founded on trust, communication, and genuine care for our clients' financial wellbeing. We do not chase volume. We do not bill by the hour. We invest deeply in every relationship and structure our engagements to align our incentives with yours. When you succeed, we succeed.

We believe that a tax return should just be the end product of a year well-planned. That philosophy -- proactive, advisory-first, and relationship-driven -- is what sets Lanphier LLP apart.