Officer Stock Acquisition

Shukri Jeries Souri, Group Vice President at EXPONENT INC, acquired 184 shares of Common Stock on September 18, 2026, at a price of $68.4452 per share. This acquisition was made under the Issuer's Dividend Reinvestment Plan. Following this transaction, Souri holds 40,873 shares of Common Stock. The filing also notes that an additional 0.288 shares were acquired, bringing the total fractional share balance held via DRIP to 0.382 shares. This includes 0.094 shares previously not reported on Form 3.