Exhibit 99.1 Insperity Announces First Quarter Results HOUSTON – May 1, 2024 – Insperity, Inc. (NYSE: NSP), a leading provider of human resources and business performance solutions for America’s best businesses, today reported results for the first quarter ended March 31, 2024. Insperity will be hosting a conference call today at 8:30 a.m. ET to discuss these results and our updated 2024 outlook and will be posting an accompanying presentation to its investor website at http://ir.insperity.com. • Q1 average ...