Nvidia

(NVDA) - Get Report

was powering ahead by 7.7% to $55.30 in premarket Instinet action Thursday.

Buyers drove up shares of the graphics processor maker after learning that the company will replace

Enron

(SYMBOL)

in the S&P 500 after the close of trading today.

Nvidia is currently a component of the S&P MidCap 400.