Nasdaq OMX Group Inc, which operates the Nasdaq exchange, is going to retool the Nasdaq-100 index containing the hundred largest nonfinancial Nasdaq stocks. The rebalancing will see Apple’s share of the index cut to 12.33 percent. Apple, which trades on Nasdaq under the AAPL ticker, currently has a big weight of 20.49 percent, or one fifth of the index. Reuters points to a document on Nasdaq’s site which states:

According to The Wall Street Journal, a rare decision comes after Apple’s meteoric rise boosted by strong sales of iOS gadgets:

Apple’s stock gained nearly 200 percent over the past two years, five percent since the beginning of 2011. On the first day of trading this year their market capitalization zoomed past the $300 billion mark. Apple is now the most-valued technology company in the world and second-largest company on the planet in market valuation, right behind Exxon-Mobil. The rebalance, which will take effect on May 2, should not have a substantial impact on Apple’s share price, but analysts expect high volume of trading today as result of the announcement and significant selling pressure by money managers tracking the index.