NEW YORK -- Facebook will join the Standard & Poor's 500 stock index, replacing technology supplier Teradyne, while Abercrombie & Fitch is downgraded from the benchmark index.

S&P Dow Jones Indices on Wednesday announced a broader reshuffling of several of its market trackers, effective after the close of trading Dec. 20.

Shares of Menlo Park-based Facebook have surged 86 percent this year and picked up nearly 4 percent in after-hours trading. The company is also joining the S&P 100 index.

Abercrombie & Fitch stock is down 31 percent in 2013 as teen retailers fade in popularity. It's being moved down to an index for companies with smaller market values, the S&P MidCap 400. The New Albany, Ohio-based company's stock shed almost 2 percent in extended trading.