Not sure where your confidence came from but a Google of “sco Microsoft” reveals:
By the mid-1980s Microsoft had gotten out of the Unix business, except for its ownership stake in SCO.[20]
By the mid-1980s Microsoft had gotten out of the Unix business, except for its ownership stake in SCO.[20]
They later filed for bankruptcy in 2007.
SCO was founded in 1979 by Larry Michels and his son Doug Michels.
https://web.archive.org/web/20061105100939/http://www.inform...
They were a partner with Microsoft maintaining a version of Xenix
You can buy 100% of shares and take it private, but that's overkill for what Microsoft wanted.