Ownership Filing for Robin Joseph Weitkamp

This filing details the ownership of Stepan Co. common stock by Robin Joseph Weitkamp, VP and GM Surfactants-INT. The report includes holdings of restricted stock units, stock appreciation rights, and performance shares, with various vesting schedules and performance periods extending up to December 31, 2028. The shares vest over three years beginning on the date shown, with some contingent on achieving performance goals. Additionally, Mr. Weitkamp has indirect ownership of 96.9 shares through the ESOP II Trust. The reporting date for this document is April 1, 2026.