X0306 4 2015-05-11 0001257640 KRONOS WORLDWIDE INC KRO 0001013005 STAFFORD THOMAS P 5430 LBJ FREEWAY, SUITE 1700 DALLAS TX 75240 1 0 0 0 Common Stock $0.01 par value 2015-08-11 4 P 0 15700 7.06 A 18700 D The price reported in Column 4 is a weighted average price. These acquisitions involved 16 purchases at prices ranging from $7.73 to $7.89 per share. The reporting person undertakes to provide to the issuer, any security holder of the issuer or the U.S. Security and Exchange Commission, upon request, the full information regarding these purchases. A. Andrew R. Louis, Attorney-in-fact, for Gen. Thomas P. Stafford 2015-05-21