Pretty sure that's not true.
Prety sure it is.
30 September 2009, Hyperion was granted an exclusive, perpetual, worldwide right to AmigaOS 3.1 in order to use, develop, modify, commercialize, distribute and market AmigaOS 4.x and subsequent versions of AmigaOS (including AmigaOS 5).
Means they have a license to use AmigaOS 3.1 for development and marketing of AmigaOS 4 and above.
Doesn't mean they own it, it actually means they don't own it, but they have the right to use it.