US-based glass manufacturer Corning is the company behind Gorilla Glass, a break-resistant glass used to protect screens that’s used on essentially all of the most popular smartphones. Today, the European Commission announced an investigation into Corning for anti-competitive practices, alleging that the glassmaker is preventing competition through exclusive supply agreements.

According to the press release, Corning requires mobile phone manufacturers to source all or nearly all of their alkali-AS glass from it, and it also grants rebates to these companies if they do so. Additionally, these phone makers must tell Corning if they receive competitive offers from other glass manufacturers. They aren’t allowed to accept these offers unless Corning cannot match or beat the price.

Similarly, Corning has agreements with companies that process raw glass, forcing them to get all or most of their alkali-AS glass from Corning. They also aren’t allowed to challenge Corning patents.

These charges reinforce how aggressive Corning is in defending its dominant position in the smartphone glass screen market. The latest Apple and Android devices, like the Google Pixel 9, usually have Gorilla Glass screens, as they’re scratch-resistant and prevent cracking or breaking. While not indestructible, the glass does hold up well against damage. However, Corning’s market dominance coupled with these practices are enough to get the EU’s attention.

This article originally appeared on Engadget at https://www.engadget.com/mobile/the-eu-is-looking-into-corning-for-alleged-anti-competitive-practices-140328416.html?src=rss