SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* SIMMONS HAROLD C (Last) (First) (Middle) 5430 LBJ FREEWAY, SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol KRONOS WORLDWIDE INC [ KRO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner X Officer (give title below) Other (specify below) Chairman of the Board
	3. Date of Earliest Transaction (Month/Day/Year) 05/21/2010
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock $0.01 par value	05/21/2010		P		1,000	A	$17.6	238,509	D
Common Stock $0.01 par value								28,995,021	I	by Valhi(1)
Common Stock $0.01 par value								17,609,635	I	by NL(2)
Common Stock $0.01 par value								79,567	I	by TFMC(3)
Common Stock $0.01 par value								54,856	I	by Spouse(4)
Common Stock $0.01 par value								2,686	I	by Contran(5)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. 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.

2. 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.

3. 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.

4. Directly held by the reporting person's spouse. The reporting person disclaims beneficial ownership of, and a pecuniary interest in, any shares of the issuer's common stock that his spouse holds.

5. 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.

Remarks:

Exhibit Index Exhibit 99 Additional Information

	A. Andrew R. Louis, Attorney-in-fact, for Harold C. Simmons	05/25/2010
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

f4kro100521hcs.txt





Exhibit 99 Additional Information



 Valhi, Inc. ("Valhi"), NL Industries, Inc. ("NL"), Harold C. Simmons,

TIMET Finance Management Company ("TFMC"), Harold C. Simmons' spouse and Contran

Corporation ("Contran") are the holders of 59.2%, 36.0%, 0.5%, 0.2%, 0.1% and

less than 0.1% respectively, of the outstanding shares of common stock, par

value $0.01 per share ("Common Stock"), of the issuer.



 Titanium Metals Corporation ("TIMET") directly owns 100% of the

outstanding common stock of TFMC. Valhi Holding Company ("VHC"), Harold C.

Simmons' spouse, The Combined Master Retirement Trust (the "CMRT"), Harold C.

Simmons, NL, Valhi, Contran and the Harold Simmons Foundation, Inc. (the

"Foundation") are the holders of approximately 26.1%, 12.0%, 8.6%, 4.1%, 0.8%,

0.5%, 0.1% and less than 0.1%, respectively, of the outstanding common stock of

TIMET. NL's percentage ownership of TIMET common stock includes 0.3% directly

held by a subsidiary of NL.



 Valhi and TFMC are the direct holders of approximately 83.0% and 0.5%,

respectively, of the outstanding common stock of NL. VHC, TFMC, the Foundation,

the Contran Amended and Restated Deferred Compensation Trust (the "CDCT"),

Harold C. Simmons' spouse, Harold C. Simmons, the CMRT and Contran are the

direct holders of 92.3%, 1.1%, 0.9%, 0.3%, 0.2%, 0.2%, 0.1% and less than 0.1%,

respectively, of the outstanding common stock of Valhi. Dixie Rice Agricultural

Corporation, Inc. ("Dixie Rice") is the direct holder of 100% of the outstanding

common stock of VHC. Contran is the holder of 100% of the outstanding common

stock of Dixie Rice.



 Substantially all of Contran's outstanding voting stock is held by

trusts established for the benefit of certain children and grandchildren of

Harold C. Simmons (the "Trusts"), of which Mr. Simmons is the sole trustee,

or is held by Mr. Simmons or persons or entities related to Mr. Simmons. As

sole trustee of the Trusts, Mr. Simmons has the power to vote and direct the

disposition of the shares of Contran stock held by the Trusts. Mr. Simmons

disclaims beneficial ownership of, and a pecuniary interest in, all Contran

shares that the Trusts hold.



 Harold C. Simmons is the chairman of the board of each of the issuer,

Valhi, TIMET, VHC, Dixie Rice and Contran and the chairman of the board and

chief executive officer of NL.



 The Foundation directly holds less than 0.1% of the outstanding shares of

TIMET common stock and 0.9% of the outstanding shares of Valhi common stock. The

Foundation is a tax-exempt foundation organized for charitable purposes. Harold

C. Simmons is the chairman of the board of the Foundation.



 The CMRT directly holds approximately 8.6% of the outstanding shares of

TIMET common stock and 0.1% of the outstanding shares of Valhi common stock.

Contran sponsors the CMRT, which permits the collective investment by master

trusts that maintain the assets of certain employee benefit plans Contran and

related companies adopt. Harold C. Simmons is the sole trustee of the CMRT

and a member of the trust investment committee for the CMRT. Contran's board

of directors selects the trustee and members of the trust investment

committee for the CMRT. Mr. Simmons is a participant in one or more of the

employee benefit plans that invest through the CMRT.



 The CDCT directly holds approximately 0.3% of the outstanding shares of

Valhi common stock.  U.S. Bank National Association serves as the trustee of

the CDCT.  Contran established the CDCT as an irrevocable "rabbi trust" to

assist Contran in meeting certain deferred compensation obligations that it

owes to Harold C. Simmons.  If the CDCT assets are insufficient to satisfy

such obligations, Contran is obligated to satisfy the balance of such

obligations as they come due.  Pursuant to the terms of the CDCT, Contran (i)

retains the power to vote the shares of Valhi common stock held directly by

the CDCT, (ii) retains dispositive power over such shares and (iii) may be

deemed the indirect beneficial owner of such shares.



 By virtue of the holding of the offices, the stock ownership and his

services as trustee, all as described above, (a) Harold C. Simmons may be

deemed to control such entities and (b) Mr. Simmons and certain of such

entities may be deemed to possess indirect beneficial ownership of shares

directly held by certain of such other entities. However, Mr. Simmons

disclaims such beneficial ownership of, and a pecuniary interest in, the

shares beneficially owned directly or indirectly by any of such entities,

except to the extent of his vested beneficial interest, if any, in shares

held by the CDCT or the CMRT. Mr. Harold Simmons disclaims beneficial

ownership of, and a pecuniary interest in, all shares of Common Stock that

Valhi, NL or TFMC directly holds.



 Harold C. Simmons' spouse is the direct owner of 54,856 shares of

Common Stock, 292,225 shares of NL common stock, 21,575,875 shares of TIMET

common stock and 203,065 shares of Valhi common stock. Mr. Simmons may be

deemed to share indirect beneficial ownership of such shares. Mr. Simmons

disclaims all such beneficial ownership.



 Harold C. Simmons directly holds 238,509 shares of Common Stock,

883,100 shares of NL common stock, 7,422,787 shares of TIMET common stock and

180,432 shares of Valhi common stock.



 A trust, of which Harold C. Simmons and his spouse are trustees and the

beneficiaries are the grandchildren of his spouse, is the direct holder of

15,432 shares of TIMET common stock and 31,800 shares of Valhi common stock.

Mr. Simmons, as co-trustee of this trust, has the power to vote and direct

the disposition of the shares of Valhi common stock the trust holds. Mr.

Simmons disclaims beneficial ownership of, and a pecuniary interest in, any

shares that this trust holds.



 NL and a subsidiary of NL directly own 3,604,790 and 1,186,200 shares

of Valhi common stock, respectively. As already discussed, Valhi directly

holds 83.0% of the outstanding shares of NL common stock. Pursuant to

Delaware law, Valhi treats the shares of Valhi common stock that NL and the

subsidiary of NL own as treasury stock for voting purposes. For the purposes

of the percentage calculations herein, such shares are not deemed

outstanding.