Russell Index Reconstitution

On average, when companies are added to the Russell indices, the share prices allegedly increase 47%, as indexed mutual funds have to buy them for their funds. And share prices for companies that fall out of the index fall 27%. I have yet to substantiate these claims, although they seem plausible.

http://www.russell.com/indexes/membership/Reconstitution/Reconstitution_changes.aspx

Inclusion into the Russell indices are predicated on the objective criteria of market capitalization, so there's no room for manipulation. Companies who get included naturally experience a rise in share prices, and it becomes self-fulfilling as index funds buying in increase more buying pressure. As an aside, it's somewhat comforting to see a handful of companies I own be included in the index.