Sony Ericsson and Motorola, Inc. have announced an agreement under which Motorola will acquire a 50% interest in UI Holdings BV, the parent company of UIQ Technology AB, which is currently wholly owned by Sony Ericsson.

Under the agreement, Motorola and Sony Ericsson will work together and jointly invest in the development of the UIQ open user interface platform.

Terms of the agreement were not disclosed. Sony Ericsson originally acquired UIQ Technology from Symbian Ltd in February 2007.

The UIQ platform is a GUI based on the Symbian OS, UIQ Technology licenses the UIQ open user interface and development platform to mobile phone vendors around the world.

Motorola and Sony Ericsson have said they are committed to further advancing UIQ as a strong, independent cross-vendor user interface for smartphones and media-centric phones.

Motorola and Sony Ericsson also plan to significantly increase their cooperation and support for the UIQ developer program.

Both companies have agreed that UIQ will be vendor and chipset independent. In addition, UIQ will be licensed on equal terms to all mobile device vendors in the industry. Sony Ericsson and Motorola are committed to expanding the shareholder base of UI Holdings to include other handset vendors.

Sony Ericsson and Motorola each have been UIQ licensees for many years and have launched several Symbian/UIQ based products including, the Sony Ericsson P1 smartphone, the new W960 Walkman phone and the Motorola MOTO Z8.