Either Micro Focus (through its acquisition of Attachmate/Novell) or Nokia (through its ownership of Bell Labs), depending on whether or not the Research Unix c

Either Micro Focus (through its acquisition of Attachmate/Novell) or Nokia (through its ownership of Bell Labs), depending on whether or not the Research Unix copyrights were part of the Unix business that AT&T sold to Novell. Bell Labs and USL were distinct business units within AT&T. That's assuming it's deemed a work-for-hire (which if it isn't makes it the property of Ken Thompson and the Ritchie estate) and that it wasn't somehow "published" before 1989 (which if it was without a copyright notice, makes it public domain - but works written before 1989 but not published until after are under copyright regardless). It's confusing stuff.