Soundwave on 14 September 2014
Obviously Nintendo. Losing Mario would be like Marvel losing Spider-Man ... probably worse honestly. Mario means more to Nintendo than even Mickey Mouse means to modern Disney.
Halo would be a massive loss to MS.
Uncharted while popular is not as big of a loss. To be honest Last of Us could probably step in and replace Uncharted as a franchise without much loss to Sony's bottom line. Losing a core third party IP like Final Fantasy or Metal Gear or GTA entirely would hurt Sony more.
