X0306 4 2016-01-10 0 0001561627 ExOne Co XONE 0001049495 ROCKWELL S KENT 127 INDUSTRY BOULEVARD NORTH HUNTINGDON PA 15642 1 1 1 0 CHAIR and CEO Common Stock, par value $0.01 per share 2016-01-10 4 P 0 1423877 9.13 A 4210555 I By S. Kent Rockwell Revocable Trust S. Kent Rockwell is the beneficiary of the S. Kent Rockwell Revocable Trust, which is the indirect, sole stockholder of Rockwell Forest Products, Inc., which is the record holder of the shares beneficially owned by Mr. Rockwell. /s/ JoEllen Lyons Dillon, attorney-in-fact for S. Kent Rockwell 2016-01-12