X0304 4 2011-09-16 0001257640 KRONOS WORLDWIDE INC KRO 0001037854 SIMMONS HAROLD C 5430 LBJ FREEWAY, SUITE 1700 DALLAS TX 75240 1 1 1 0 Chairman of the Board Common Stock $0.01 par value 2011-09-16 4 P 0 100 19.89 A 144812 I by Spouse Common Stock $0.01 par value 2011-09-16 4 P 0 5000 19.90 A 149812 I by Spouse Common Stock $0.01 par value 2011-09-16 4 P 0 9900 20.00 A 159712 I by Spouse Common Stock $0.01 par value 57990042 I by Valhi Common Stock $0.01 par value 35219270 I by NL Common Stock $0.01 par value 518440 D Common Stock $0.01 par value 373334 I by TFMC Common Stock $0.01 par value 5372 I by Contran Open market purchase by the reporting person's spouse. Directly held by the reporting person's spouse. The reporting person disclaims beneficial ownership of any shares of the issuer's common stock that his spouse holds. Directly held by Valhi, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationship to the reporting person. Directly held by NL Industries, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationship to the reporting person. Directly held by TIMET Finance Management Company. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationship to the reporting person. Directly held by Contran Corporation. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationship to the reporting person. Robert D. Graham, Attorney-in-fact, for Harold C. Simmons 2011-09-19