The S&P 500 ( ^GSPC 1.07% ) is the most highly regarded stock market index in the U.S., comprised of the 500 largest publicly traded companies in the country. Many investors consider it to be the most reliable gauge of overall stock market performance, thanks to the breadth of its member companies.

To be a member of the S&P 500, a company must meet the following criteria:

Be based in the U.S.

Have a market cap of at least $22.7 billion

Be highly liquid

A minimum of 50% of its outstanding shares must be available for trading

Must be profitable on a generally accepted accounting principles ( GAAP ) basis in the most recent quarter

In aggregate, must be profitable over the preceding four quarters

Netflix ( NFLX +1.18% ) first earned its spot in the S&P 500 in Dece

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