Leave it to Tesla army of momentum-chasing fanatics to send the stock surging not once but twice on S&P inclusion news.

Two weeks after TSLA hit an all-time high after S&P unexpectedly announced that it would include the EV maker in the S&P on December 21, moments ago - in an anticipated announcement - S&P Dow Jones Indices said it has determined that it will add Tesla to the S&P 500 at its full float-adjusted market capitalization weight effective prior to the open of trading on December 21.

Ahead of the determination, S&P considered the expected liquidity of Tesla and the market’s ability to accommodate significant trading volumes. In the end, it picked the simplest solution: basically absorbing the entire company in one go.

S&P also said that after the market close on December 11, pro-forma files will be distributed, and a press release will be published announcing which company Tesla will replace in the S&P 500.

Considering that the S&P inclusion is expected to result in some $11 billion in mandatory purchases it is safe to say that TSLA has gotten more than a fair share of upside, with the stock surging by $200 since the S&P announcement, an addition of more than $200 billion to its insane market cap. What's better is that after surging on Nov 16, the stock spiked some more for good measure after today's announcement - as if it was a surprise - with the stock up 5% after the close, or adding an additional $20BN in market cap on the exact same news. Because of efficient "markets".

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So will Tesla just keep rising to infinity?

Maybe, but according to Gary Black, who was chief executive of Aegon Asset Management from mid-2016 through September, after the initial buying into the Dec. 21 inclusion, the stock may pull back if history is any guide. Black said the shares may fall about 10% to 20%, a pattern that would be consistent with what happened to Facebook after its entry into the S&P 500 seven years ago.

Then again, seven years ago central banks weren't pumping $300 billion into the market every month.