Mark W. Sullivan, EA founded Sullivan Consulting in 1998. He specializes in federal tax controversy representation, appeals and consulting on behalf of individuals, businesses, law, and accounting firms nationwide. In addition, he has served as the consulting and expert witness in numerous civil and criminal cases in multiple federal district courts.

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Mark has an unlimited Enrolled Agents license and is admitted to practice before the Internal Revenue Service based on his extensive experience as a Revenue Officer in New York, NY, St. Louis, MO and Washington, D.C..