Tesla joining S&P 500; shares jump 10% (updated)

• Tesla (NASDAQ:TSLA) has jumped 10% postmarket on heavily awaited word that it's joining the S&P 500 index.
• The company will join the index prior to the open on Monday, Dec. 21, coinciding with the quarterly rebalance.
• But due to the size of the addition, "S&P Dow Jones Indices is seeking feedback through a consultation to the investment community to determine if Tesla should be added all at once on the rebalance effective date or in two separate tranches ending on the rebalance effective date."
• And the company it's replacing will be named later, S&P says.
• Updated: With an approximate pro forma weight of about 1.01% in the S&P 500, the Index Committee estimates the funding trade to be $51B, one of the largest in S&P history. "However, TSLA itself is very liquid, and adding the stock at the upcoming December quarterly rebalancing coincides with the expiration of stock options, stock futures, stock-index options, and stock-index futures, which may help facilitate the funding trade," S&P Dow Jones Indexes says.