Exhibit 99.1 Vertex Announces First Quarter 2025 Financial Results KING OF PRUSSIA, PA – May 7, 2025: Vertex, Inc. (NASDAQ: VERX) ("Vertex" or the "Company"), a leading global provider of indirect tax solutions, today announced financial results for its first quarter ended March 31, 2025. "Vertex continued to perform well in the first quarter, setting us up for a strong 2025," said David DeStefano, Vertex's President, Chief Executive Officer and Chairperson of the Board. "Our financial results were in line ...