Sec Form 4 Filing - ROCKWELL S KENT @ ExOne Co - 2013-09-09

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ROCKWELL S KENT 2. Issuer Name and Ticker or Trading Symbol ExOne Co [ XONE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chair and CEO (Last) (First) (Middle) 127 INDUSTRY BOULEVARD 3. Date of Earliest Transaction (MM/DD/YY) 09/09/2013 (Street) NORTH HUNTINGDON, PA15642 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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, par value $0.01 09/09/2013 S 1,318,400 D $ 59.055 3,162,628 ( 1 ) I By S. Kent Rockwell Revocable Trust

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ROCKWELL S KENT 127 INDUSTRY BOULEVARD NORTH HUNTINGDON, PA15642 X X Chair and CEO Signatures /s/ JoEllen Lyons Dillon, attorney-in-fact for S. Kent Rockwell 09/11/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )S. Kent Rockwell is the beneficiary of the S. Kent Rockwell Revocable Trust, which is the indirect, sole stockholder of Rockwell Forest Products, Inc. and Rockwell Holdings, Inc. which are the record holders of the shares beneficially owned by Mr. Rockwell. On September 9, 2013, Rockwell Holdings, Inc. and Rockwell Forest Products, Inc. entered into an underwriting agreement with FBR Capital Markets & Co., as Representative of the several Underwriters, pursuant to which they agreed to sell 305,028 and 1,013,372 shares of Common Stock of The ExOne Company, respectively. The transaction is expected to close on September 13, 2013.

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).

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