On February 24, 2023, the Board of Directors (the “Board”) of Rubicon Technology, Inc. (the “Company”) appointed Joseph Ferrara as the Company's Executive Officer, effective immediately. On February 20, 2023, Timothy E. Brog, the former Chief Executive Officer, President and Acting Chief Financial Officer of the Company, tendered his resignation as a member of the Board. The resignation was effective upon the receipt by Mr. Brog of a settlement payment pursuant to the Separation Agreement (as defined below), which occurred on February 22, 2023.

Mr. Brog's resignation from the Company as Chief Executive Officer, President and Acting Chief Financial Officer was previously announced on December 12, 2022 and was effective on January 6, 2023. Mr. Brog's resignation as a member of the Board was not the result of any disagreements with the Company on any matters relating to its operations, policies or practices.