• Jimmy Martens

    Jimmy Martens, Attorney and CPA, is a partner with Martens, Todd & Leonard,
    a Texas tax controversies litigation law firm located in downtown Austin, Texas.

    Mr. Martens has tried tax cases through both the Texas Supreme Court and the U.S. Supreme Court. He and others at Martens, Todd & Leonard limits their law practice to challenging Texas franchise and sales tax assessments and denied refund claims

    in audits, administrative hearings, and in the state courts of Texas though the Texas Supreme Court.

    He is board certified by the Texas Board of Legal Specialization in Tax Law.

  • Lacy Leonard

    Lacy Leonard, trial attorney, is a partner with Martens,Todd & Leonard, a tax controversies litigation law firm located in downtown Austin, Texas.

    She and other members of her law firm limit their practices to challenging Texas franchise and sales tax assessments and denied refund claims in audits, administrative hearings, and in the state courts of Texas though the Texas Supreme court.

  • Gordon Martens

    Gordon Martens, trial and appellate attorney with Martens, Todd & Leonard, a boutique tax litigation law firm located in
    downtown Austin, Texas. 

    Gordon and other members of his law firm represent clients during Texas tax audits, in Administrative Hearings, and in the Texas
    trial and appellate courts.

    He has represented a wide variety of businesses with a focus on the oil, gas, construction, and technology industries.   


  • Jonathan Bailey

    Jonathan is an Experienced Manager within BDO’s Southwest State and Local Tax practice specializing in state and local sales and use tax. He has experience serving multiple industries including oilfield services companies, healthcare, manufacturing, retail, technology, and agriculture.

  • Chris Blackwell

    Chris Blackwell is a Manager in Deloitte’s Austin, Texas office and specializes in indirect taxation.

    Chris provides a broad array of tax consulting, advisory, and compliance services, including audit defense and mitigation, tax refund prosecution, controversy representation, and settlement and voluntary self-disclosure negotiation.

  • Bobby Bui 

    Bobby Bui is a Texas-based State and Local Tax (SALT) attorney advising clients on a broad range of SALT matters. 


    His industry focus is in the oil & gas, EPC and manufacturing sectors. His clients include several global super majors as well as numerous oil & gas commodity trading companies.

  • Nathan Cahill

    Nathan has 20 years of experience in sales and use tax. His career began in Public Accounting, where he spent nearly a decade in the Big Four and a Top 10 firm splitting his time between state income-franchise tax and sales and use tax. He transitioned into industry where he spent over a decade focused on sales tax within the energy industry, specifically oil and gas exploration & production and oilfield services. 

  • Gary Dressler

    Gary Dressler is a Senior Manager with EisnerAmper. He has more than 27 years of state and local tax experience.

    His primary focus is on all matters pertaining to Louisiana state and local taxation, including planning, audit representation, and representation at both state and local appeals hearings.

    Gary previously spent 19 years in the retail industry, two years in the tax department of an oil and gas company, and over 18 years with a Big Four firm where he served as the State Tax Resource Network member for Louisiana and Mississippi until 2015.

  • John LaBorde

    John LaBorde is a Managing Director at Moss Adams LLP. With over 30 years of experience in taxation, John has worked in industry and public accounting, focused on assisting clients in the energy industry. His energy industry experience covers a broad range including exploration & production, energy services, downstream energy, midstream and interstate pipelines, power generation including renewable energy, electricity distribution and energy trading.

  • Natalie A. Maloney

    Natalie is a partner with Michel Gray & Rogers LLP, focusing her practice on property tax litigation, mediation, and settlement. Natalie represents commercial property owners at the administrative and trial levels throughout Texas.  She focuses her time on tax reductions for stand-alone retail buildings, a national drug store chain, shopping centers, multi-family, hotels, industrial warehouses, and business personal property.

  • Stephen Metz

    Stephen Metz is a Senior Manager with KPMG LLP in Denver, Colorado. Mr. Metz has represented clients in state and local tax matters since 1997. Prior to joining KPMG LLP, Mr. Metz worked at a boutique law firm specializing in Colorado Special Metropolitan Districts and served as the Law Clerk for the Honorable Edward A. Simons in Denver District Court.

  • Tom A. Smith

    Tom Smith leads BDO’s Southwest Region State & Local Tax team and is the office managing partner in Tulsa, Oklahoma. Mr. Smith is well known for his knowledge in tax controversy, he has recovered millions of dollars for his clients through sales tax refund projects (reverse audits). He has vast experience managing taxability research projects and regularly worked on due diligence projects both pre and post-acquisition. Mr. Smith is also well known in Nashville, Tennessee, where he developed a significant expertise in the healthcare industry. He also has extensive experience in the energy industry, serving clients in both Oklahoma and Texas.  Mr. Smith began his career began as an auditor for the Texas Comptroller of Public Accounts in 1990.  Prior to joining BDO as a partner, he spent decades working at large national and international CPA firms.

  • Tim Van Valen

    Tim Van Valen is a New Mexico attorney with 35 years of experience.  For over 25 years, his practice has been devoted almost exclusively to New Mexico taxation issues for businesses, primarily large, multi-state or multinational. Common topics are tax research and planning, litigation and appeals, legislation and government affairs, regulations, private letter rulings, and unique issues relating to business activities involving Native American tribes, nations, and pueblos.

  • Dwayne Van Wieren

    Dwayne Van Wieren is a CPA and Tax Partner with Deloitte Tax LLP in Los Angeles, California. Mr. Van Wieren is a former sales and use tax auditor with the Texas Comptroller of Public Accounts. Mr. Van Wieren currently leads Deloitte’s national U.S. indirect tax services team, which consists of 175 sales, use and excise tax professionals.