From the news.com article

Posted Mar 14, 2003 5:37 UTC (Fri) by MLKahnt (guest, #6642)
In reply to: From the news.com article by Ross
Parent article: A look at the SCO complaint

Psst - Solaris is the Sun version of Unix arising from the work of Sun and AT&T Bell Labs that became SVR4 (which was supposed to unify BSD and SVR3 code), and led to the OSF counter-project. Ironically, iirc, at one point AIX was targetted as being some key parts of OSF o/s, partly because of design, and partly because of the significant lack of AT&T code, due to the substantively different underlying design of AIX. That difference meant that there was considerably less AT&T code that would need replacement.

SCO's role as the owner of Unix(tm) is about equivalent to that of Michael Jackson's wrt The Beatles - they may "own" the Intellectual Property rights, but they have done no creative development of that property.

The Unix(tm) API (The System V Interface Definition - SVID) is the only "standard" of Unix(tm), to my recollection, which was further formalised (and taken out of the IP realm) by POSIX.