The European Commission (EC) has opened an antitrust investigation into US-based glass-maker Corning, claiming that its Gorilla Glass has dominated the mobile phone screen market due to restrictive deals and licensing. Corning's shatter-resistant alkali-aluminosilicate glass keeps its place atop the market, according to the EC's announcement, because it both demands, and rewards with rebates, device makers that agree to "source all or nearly all of their (Gorilla Glass) demand from Corning." Corning also allegedly required device makers to report competitive offers to the glass maker.