Robbins Geller Rudman & Dowd LLP (“Robbins Geller”) (http://www.rgrdlaw.com/cases/rubicon/) announced that a class action has been commenced in the United States District Court for the Northern District of Illinois on behalf of purchasers of Rubicon Technology (“Rubicon”) (NASDAQ:RBCN) common stock in the Company’s public offering on or about March 19, 2014 (the “Offering”).

If you wish to serve as lead plaintiff, you must move the Court no later than 60 days from today. If you wish to discuss this action or have any questions concerning this notice or your rights or interests, please contact plaintiff’s counsel, Samuel H. Rudman or David A. Rosenfeld of Robbins Geller at 800/449-4900 or 619/231-1058, or via e-mail at djr@rgrdlaw.com. If you are a member of this class, you can view a copy of the complaint as filed or join this class action online at http://www.rgrdlaw.com/cases/rubicon/. Any member of the putative class may move the Court to serve as lead plaintiff through counsel of their choice, or may choose to do nothing and remain an absent class member.

The complaint charges Rubicon, certain of its officers and directors and the underwriters of the Offering with violations of the Securities Act of 1933. Rubicon is a vertically integrated, advanced electronic materials provider specializing in monocrystalline sapphire, which is commonly used as a substrate (i.e., base layer) in LED lighting technology.

On December 6, 2013, Rubicon filed with the SEC an amended shelf registration statement (the “Form S-3A”), which included a form of prospectus (the “Prospectus”) authorizing the Company and to-be-identified “selling stockholders” to sell up to US $100,000,000 worth of shares of Rubicon common stock, at any time, in one or more offerings. On March 19, 2014, Rubicon filed with the SEC a prospectus supplement (the “Prospectus Supplement”), offering to register for sale at $13.00 per share 2.5 million shares of Rubicon common stock (not including an overallotment of 375,000 shares) by selling shareholder Cross Atlantic Funds (a group of funds controlled by one of Rubicon’s directors). The Offering was sold pursuant to the Form S-3A, the Prospectus and the Prospectus Supplement (jointly referred to herein as the “Registration Statement”).

The complaint alleges that the Registration Statement contained untrue statements of material facts, omitted to state other facts necessary to make the statements made not misleading and was not prepared in accordance with the rules and regulations governing its preparation. Specifically, the Registration Statement negligently failed to disclose material trends, events and uncertainties known to management that were reasonably expected to have a material impact on the Company’s income from continuing operations, including the reversal of its trend of shrinking losses, higher-than-expected development costs and inventory write-offs due to Rubicon’s inability to sell certain of its wafers during its 2014 first quarter at prices greater than their cost to manufacture, causing such inventory to be impaired under applicable accounting rules and regulations.

Then on May 1, 2014, the Company issued a press release and hosted a conference call regarding its first quarter of 2014. The Company reported disappointing financial results and revealed, among other things, that the trend of shrinking gross losses, operating losses, and losses per share from the prior quarters had dramatically reversed in the first quarter of 2014, reporting substantial increases in gross losses of $7.5 million, losses from operations of $10.9 million, and losses per share of $0.43. After the earnings call on May 1, 2014, the price of Rubicon common stock declined by 16%, from about $10 per share to $8.51 per share, and declined another almost 6% to $8.01 per share on May 5, 2014. The stock currently trades at below $4.00 per share, a 70% decline from the Offering price.

Plaintiff seeks to recover damages on behalf of all purchasers of Rubicon common stock in the Company’s public offering on or about March 19, 2014 (the “Class”). The plaintiff is represented by Robbins Geller, which has extensive experience in prosecuting investor class actions including actions involving financial fraud.

Robbins Geller, with 200 lawyers in ten offices, represents U.S. and international institutional investors in contingency-based securities and corporate litigation. The firm has obtained many of the largest securities class action recoveries in history, including the largest securities class action judgment. Please visithttp://www.rgrdlaw.com for more information.