Apple (NasdaqGS: AAPL) was down nearly 3% in Monday’s premarket and the stock looks ready for another test of the key $500-a-share level as the tech giant weighs down the popular PowerShares QQQ (NasdaqGM: QQQ), an ETF hitched to the Nasdaq-100 Index.

AAPL is the largest individual stock holding in QQQ at 15.5% of the portfolio.

The company has cut orders for LCD screens and other parts for the iPhone 5 this quarter due to weak demand, Reuters reports.

Apple shares have corrected more than 20% since the September high, which has hurt the tech-heavy QQQ. The Nasdaq-100 has been trailing the S&P 500 due in large part to the weakness in Apple.