Exchange traded funds tracking the technology sector, the largest sector weight in the S&P 500, have not been immune from the recent pullback in U.S. stocks and with tech earnings season underway, some investors are taking a cautious approach to the sector.

The PowerShares QQQ (NasdaqGM: QQQ), the NASDAQ-100 tracking ETF, lost $8.26 billion in assets over the past six weeks, reports Namitha Jagadeesh for Bloomberg. Options also appear to be pricing in a big move in QQQ, one of the largest U.S. ETFs of any type.

Last week, options pricing in a 10% drop for QQQ cost almost nine points more than those pricing in a 10% gain for the ETF and two of the three most-owned contracts on QQQ were bearish, according to Bloomberg.

Some investors are pointing to valuation concerns on the NASDAQ-100. QQQ had a P/E ratio of just over 20 at the end of the third quarter, according to PowerShares data. That compares with 22.6 at the end of the first quarter and is well below the P/E of 34 the ETF sported at the end of 1999, the height of the tech bubble. [The Evolution of QQQ]

QQQ is still tech heavy with a 59.5% weight to the sector and the ETF allocates over 29% of its combined weight to Apple (NasdaqGS: AAPL), Microsoft (NasdaqGS: MSFT) and both classes of Google stock. However, the ETF looks far different today than it did in the month leading up to the bursting of the tech bubble in 2000.

For example, QQQ’s current weight of 15.1% to the health care sector is more than double what it was in 1999. Additionally, the fund has benefited from tech’s recent ascent up the U.S. dividend totem pole. QQQ has a trailing 12-month yield of 1.42%, up about 60 basis points from the height of the tech bubble. Six of QQQ’s top-10 holdings pay dividends. [The Rise of Tech Dividends]