In the last trading, U.S. stocks gained after a volatile session. Among the top ETFs, (SPY Quick QuoteSPY - Free Report) gained 1%, (DIA Quick QuoteDIA - Free Report) added 0.4% and (QQQ Quick QuoteQQQ - Free Report) moved 1.7% higher on the day.

Two more specialized ETFs are worth noting as both saw trading volume that was far outside of normal. In fact, both these funds experienced volume levels that were more than double their average for the most-recent trading session. This could make these ETFs the ones to watch out for in the days ahead to see if this trend of extra-interest continues.

(VIOO Quick QuoteVIOO - Free Report) : Volume 4.46 Times Average

This small-cap ETF was in the spotlight as around 133,000 shares moved hands compared with an average 31,000 shares a day. We also saw some price movement as VIOO gained 1.5% in the last session.

The move was largely the result of upbeat GDP growth data, which showed that the economy grew at a record 33.1% annual rate in the third quarter. The solid data could have a big impact on small-cap stocks like the ones that we find in this ETF portfolio. VIOO has gained 4.2% over the past month and carries a Zacks ETF Rank #3 (Hold) with a Medium risk outlook.

(PXJ Quick QuotePXJ - Free Report) : Volume 3.30 Times Average

This energy ETF was under the microscope as nearly 50,000 shares moved hands. This compares with an average trading volume of roughly 16,000 shares and came as PXJ added 1.6% in the last trading session.

The movement can largely be blamed on a 5% plunge in oil price that could weigh on energy ETFs. PXJ has tumbled 6.3% in a month’s time. It has a Zacks ETF Rank #5 (Strong Sell) with a Medium risk outlook.

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