Volume Explosion In Today's Trading Session (QQQQ, SPY)

Volumes exploded today as the Dow Jones Industrial Average dipped below 10,000 briefly this afternoon. The latest reports are that the market slide which began around 2:30 EST was triggered by an erroneous $16 billion sell order in the S&P e-mini futures contract.

Volume in the SPDR S&P 500 ETF (NYSE: SPY) was 612.06 million compared to a daily average of 198.33 million. The PowerShares QQQ Trust ETF (NASDAQ: QQQQ) traded 273.83 million versus a daily average of 81 million. Today's action follows the recent trend of light volume on up days and heavier volume on down days in the U.S. equity markets. This could be an ominous sign of things to come, as days and weeks of positive gains can be taken out in the blink of an eye on huge volume surges.