When Google effectively splits its stock on Wednesday, S&P Dow Jones Indices will do something unprecedented: It will keep both the old Google shares and the new ones in the S&P 500. That means the S&P 500 will technically have 501 components, though it will still have only 500 companies.
In the past, S&P Dow Jones Indices, the company that runs the
S&P 500, has not kept the additional shares that more than 40
S&P 500 companies offer in the index.
In fact, in a February
press release, the company announced that it would switch Google from
the Class A shares (which will trade under the ticker "GOOGL") to the
class C shares (which will trade under the ticker "GOOG," and are likely
to be more liquid).
But in a March press release, it revised
that decision, and said both the Class A and Class C shares will be
included in the S&P 500 (as well as in the S&P 100).