I would like to give Google the benefit of doubt but since AAPL doesn't even show up at the auto-complete, it clearly looks like a prank by an employee.
Guess I'll stick with Yahoo!
Financial data sites are not a good place to be pranking your users.
That alone makes me seriously doubt that this is an easter egg, if it is google will have easter egg all over its oos.
So technically it should only show Stocks based results not keyword based results.
site:finance.google.com sell "quotes & news"
The top results is what you would get if it was a neutral algo, used by main google service.
The apple redirect is not neutral and is not a result of any algorithm.
edit: I'm not asserting that this is on purpose or not, I'm just saying that that "proof" demonstrates nothing.