Tesla to join S&P 500 as its biggest new member ever

• The move opens Tesla up to a massive investor base: roughly $11 trillion worth of investment funds that track the index.
• Tesla would be the 10th biggest S&P 500 component, ahead of Johnson & Johnson.

Catch up quick: The company met the final requirement for eligibility — four consecutive quarters of profitability — when it reported its Q2 results in July. But the company was passed over when S&P Dow Jones Indices switched up the index's components in September.

• Wall Street analysts speculated that the reason was because of Tesla's dependency on the sale of regulatory credits to other automakers — without which, it wouldn't be profitable on a quarterly basis.
• Shares of Tesla, which ran up earlier this year on the expectation it would be added to the index, rose roughly 9% in after-hours trading.

Details: The move is effective on Dec. 21.

• Because Tesla is such a massive addition to the index, the committee is still trying to figure out whether the company should be added all at once or in two separate tranches.