Rubicon Technology, Inc. Stock: price and directors' dealings · United States · SEC (Form 4)

About Rubicon Technology, Inc.

Rubicon Technology, Inc. (ticker RBCN) is a U.S.-based advanced materials company historically focused on monocrystalline sapphire and related optical and industrial components. The company was incorporated in Delaware on February 7, 2001, and built its business around growing, fabricating, and finishing sapphire-based parts used in high-performance applications. Its core product set includes sapphire windows, blanks, domes, tubes, rods, wafers, and other precision components. These products serve demanding end markets such as defense and aerospace, specialty lighting, instrumentation, sensors and detectors, semiconductor processing equipment, electronic substrates, medical devices, and laser systems. Rubicon has positioned itself as a technical supplier in a niche where crystal quality, dimensional precision, and the ability to produce very large or ultra-thin parts can matter more than scale alone. Historically, the company operated from a manufacturing base in Bensenville, Illinois, and emphasized its U.S. customer footprint while also serving select international applications. From a market-structure perspective, Rubicon competes in a highly competitive and specialized segment, where qualification cycles, application performance, and reliability of supply are critical differentiators. On the public-market side, Rubicon was formerly listed on the Nasdaq Capital Market under RBCN, but it voluntarily delisted effective December 30, 2022. Since January 3, 2023, the common stock has traded on the OTCQB Market under the same ticker. For investors in French-speaking markets, that distinction matters: Rubicon is no longer a NYSE/NASDAQ-listed equity, even though it remains a U.S. issuer with a long operating history. Recent public disclosures suggest a more limited reporting profile after the delisting and deregistration process, so the available operating narrative is narrower than for fully listed peers. In practical terms, the investment case now centers on the company’s technical sapphire know-how, its legacy industrial assets, and its ability to create value in small but strategically important high-specification markets.