Exhibit 99.1 Stepan Reports First Quarter 2026 Results Northbrook, Illinois, April 28, 2026 -- Stepan Company (NYSE: SCL) today reported: First Quarter 2026 Highlights "We are executing Project Catalyst safely and in line with expectations despite early quarter weather- related impacts and the new geopolitical challenges. Global adjusted EBITDA was down $7.9 million, or 14%, driven by our Surfactants business. Surfactants EBITDA was down due to higher oleochemicals prices, the cold snap in the U.S., product ...