It is called an Involuntary Conversion (http://www.law.cornell.edu/uscode/text/26/1033)
There are a couple of assumptions; the big one being that Stirling converts the sale into some other enterprise that is “similar or related in use”. I'm not aware of Sterling's specific business structure but I assume that he has tax lawyers at his disposal that could make sure he complies.
Even in the worse case, it would be treated as capital gains, not regular income.
Thanks.