Exhibit 99.3

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D (including amendments thereto) with respect to the shares of Common Stock, $0.001 par value, of Rubicon Technology, Inc. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated:  November 17, 2017	Bandera Master Fund L.P.
	By:	Bandera Partners LLC its Investment Manager
	By:	/s/ Jefferson Gramm
		Name:	Jefferson Gramm
		Title:	Managing Director

Bandera Partners LLC
By:	/s/ Jefferson Gramm
	Name:	Jefferson Gramm
	Title:	Managing Director

/s/ Gregory Bylinsky

Gregory Bylinsky

/s/ Jefferson Gramm

Jefferson Gramm