“Every art and every inquiry, and likewise every action and choice, seems to aim at some good, and hence it has been beautifully said that the good is that at which all things aim.” -Aristotle, Nicomachean Ethics, Book 1, Chapter 1

As a Wyoming Trust and Estates Attorney, Matthew Grupp leads by example at The Grupp Law Firm LLC. He champions his clients’ needs and seeks opportunities to help families flourish. Matthew has experience at every level of estate planning. He believes that each estate, whether simple or complex, represents a client’s life work, and therefore should be meaningfully gifted and carefully protected. While tax planning is important and very important to our planning, the meaning for the gift is the the chief concern.

Matthew has extensive experience as a Private Family Trust Company and Family Office executive representing ultra-affluent clients, who include entrepreneurs, corporate executives, and families with inherited wealth. Matthew coordinates with his clients’ other professional advisors to best address his clients’ family and business objectives.

From 1997-2005, Matthew Grupp worked as a Senior Tax Manager in the Mergers & Acquisitions practice in the Los Angels and San Francisco office at Deloitte & Touche, LLP. His work concentrated on Tax Strategies for Corporate Acquisitions, Dispositions, Spin-Offs, Joint Ventures, Financings, Reorganizations & Restructurings. This work was divided between Private Equity and Strategic transactions for many market leaders, to include Texas Pacific Group, Black Stone, KKR, Dole Food, Pacificare Health, and Washington Mutual. In 2005, he organized The Grupp Law Firm and shifted his focus to Trust and Estate Planning, with a concentration on the needs of business owning clients. That said, he is happy to help non-business owning clients as well.

He earned a B.A. in Classical Languages (Greek and Latin) and Philosophy from the University of Montana, a J.D. from the University of Montana School of Law, an LL.M. in Taxation from the New York University School of Law, and a Masters of Arts in Philosophy (with a concentration in Christian Wisdom) from Holy Apostles College & Seminary. Matthew and his wife are the proud parents of eleven children and seven grandchildren. Matthew enjoys reading Aristotelian and Thomistic philosophy.

Affiliations & Community Engagement

• Wyoming State Bar Estate Planning, Elder Law, Trust & Probate Section
• Wyoming State Bar Business Law Section (Past President)
• The Wealth Counsel
• Family Office Exchange
• American Bar Association
• Wyoming State Bar Association
• Idaho State Bar Association
• New York State Bar Association
• Catholic Parish Adult Religious Education Volunteer

“The old that is strong does not wither, deep roots are not reached by the frost.” – J.R.R. Tolkien

Theodore focuses his estate planning practice on understanding a family’s vision for the future and developing a plan around it. He has found that tax saving strategies should be harmonized with the family’s unique goals in order for the resulting estate plan to be truly beneficial.

Prior to joining The Grupp Law Firm, Theodore lived and practiced law in New York City. He began his legal career at a boutique law firm there, advising on the tax consequences of real estate transactions involving New York City real property and assisting on tax matters for large estates. He then developed his own law practice, planning estates around the New York estate tax cliff and counseling small business owners on tax consequences and strategies (e.g., Qualified Small Business Stock under Section 1202).

In October 2026, he joined The Grupp Law Firm because of an alignment of his values and the legal practice that he saw flourishing at the firm.

He graduated cum laude from the University of California, Irvine, School of Law. While there, he earned a Juris Doctorate and an LL.M. (Taxation).

He spends his free time keeping active by hiking, skiing, running and engaging in other fitness endeavors. He has a great love of literature, including the ancient epic poems and a handful of modern English writers.

Affiliations & Community Engagement

• American Bar Association
• New York State Bar Association
• New York City Bar Association’s Committee on the Taxation of Business Entities (Committee Member)

“Don’t be afraid to give up the good to go for the great.” -John D. Rockefeller

Dena Mertz is Vice President of Operations at The Grupp Law Firm LLC. In her role, she is the project manager and coordinator between HR, interns, Sales, Tax & Accounting, and IT. By developing initiatives and overseeing projects, she ensures that the teams at The Grupp Law Firm complete these in a timely manner. She also ensures that collaborative projects are efficiently carried out and that resources are properly allocated among departments.

Previously Dena has co-owned and managed a riverboat company, worked with the National Park Service, and served as Director of Operations at a private school. She has a United States Coast Guard 100 Ton Masters License. Dena earned a Bachelor of Science degree in Health Science with a concentration in Health Administration from Armstrong Atlantic State University and a Culinary Arts Degree from Savannah Culinary Institute. In her spare time, she enjoys kayaking and hiking.

Affiliations and Community Engagement

National Forest Trail Ambassador

Board Member at Lucky’s Place Animal Humane Association of Star Valley

A dead thing can go with the stream, but only a living thing can go against it.” – G.K. Chesterton

As a Certified Trust & Fiduciary Advisor, Michael leads the private client services team to address clients’ concerns, coordinate firm resources and third parties, and empower clients to achieve their aspirations. Michael has been an integral part of the team providing private client services since April 2007. Michael and his team administer clients’ trusts and private family trusts companies, and provide and coordinate family office services. The team strives to mark every interaction with judgment, courtesy, and diligence.

Michael earned a BS in Human Services from California State University, Fullerton and a MA in Counseling from Franciscan University of Steubenville, OH. Previously Michael worked as a Supervising Children’s Social Worker for Los Angeles County and as a court officer in the Los Angeles Superior Court. Michael is a dedicated husband, father of five children, and grandfather of three.