I have sold 2 websites now, both projects which where too time consuming really, but good rankings, so I sold both (two seperate sales to 2 different people) very recently to my competitors for a good price. The rankings are exactly the same. Both domains have totally new whois data and both sites are hosted on new servers.
So I wonder what part of the sale is devalued? because doesnt seem to be in this case.. Why should it be? Because effectively all that happened was the business was sold.
But at which point does Google believe a business was sold OR a domain was bought for SEO? I struggle to see how Google can accurately predict the motives behind either case - perhaps if they smacked a 301 on it straight away, then yeah - but in any other case? I am not so sure.
Perhaps 3 factors are considered:
Whois / ip changes