Well, you can know, by looking at whether or not there's a change in stock price upon announcement of inclusion in an index, right? https://www.nber.org/digest

Well, you can know, by looking at whether or not there's a change in stock price upon announcement of inclusion in an index, right? https://www.nber.org/digest/nov13/w19290.html https://www.nber.org/digest/nov13/w19290.html It appears that it's not entirely priced in.