Shares of tech bellwethers Apple (NasdaqGS: AAPL) and Microsoft (NasdaqGS: MSFT) fell Monday morning as traders kept their eye on a special rebalancing of the Nasdaq-100 Index.

Nasdaq in early April said the benchmark would undergo a special rebalance before the market’s open on May 2. Apple is expected to see its weight in the Nasdaq-100 cut to 12.3% from over 20%, according to slides prepared by the Nasdaq.

The Nasdaq-100 is the tracking index for the tech-heavy PowerShares QQQ (NasdaqGM: QQQ), one of the largest and most actively traded exchange traded funds (ETFs).

Other large holdings such as Microsoft, Oracle (NasdaqGS: ORCL), Intel (NasdaqGS: INTC), Cisco (NasdaqGS: CSCO) and Google (NasdaqGS: GOOG) are expected to see their weightings in the Nasdaq-100 rise after the reshuffle.

PowerShares QQQ was fractionally higher in morning action. The ETF came into the session with an 8.6% year-to-date gain, according to Morningstar.

PowerShares QQQ

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