In the last trading session, Wall Street showed strength on the back of strong earnings releases. Among the top ETFs, (SPY Quick QuoteSPY - Free Report) climbed 0.3% and (DIA Quick QuoteDIA - Free Report) rose 0.2% while (QQQ Quick QuoteQQQ - Free Report) moved 0.1% lower 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.

(VHT Quick QuoteVHT - Free Report) : Volume 3.85 Times Average

This healthcare ETF was in the spotlight as around 856,000 shares moved hands compared with an average of 275,000 shares a day. We also saw some price movement as VHT lost 0.2% in the last session.

The move was largely the result of investors’ flight to a defensive sector amid higher volatility and uncertainty that could have a big impact on the healthcare stocks like the ones we find in this ETF portfolio. VHT has plunged 8.6% over the past month and carries a Zacks ETF Rank #1 (Strong Buy) with a Medium risk outlook.

VOT: Volume 3.40 Times Average

This mid-cap ETF was under the microscope as nearly 437,000 shares moved hands. This compares with an average trading volume of roughly 238,000 shares and came as VOT shed 0.08% in the last trading session.

The movement can largely be blamed on the volatile market as these have the potential to move higher than the large and small-cap counterparts in turbulent times. VOT is down 21.4% in a month’s time and has a Zacks ETF Rank #2 (Buy).