In the last trading session, Wall Street gained with all the three gauges notching their fourth consecutive gains on the back of a drop in Treasury yields. Among the top ETFs, (SPY Quick QuoteSPY - Free Report) climbed 1.5% and (DIA Quick QuoteDIA - Free Report) rose 1.1%, while (QQQ Quick QuoteQQQ - Free Report) moved 2.1% 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.

(XHS Quick QuoteXHS - Free Report) : Volume 7.96 Times Average

This healthcare ETF was in the spotlight as around 30,000 shares moved hands compared with an average of 4,000 shares a day. We also saw some price movement as XHS rose 3.8% 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 healthcare stocks like the ones we find in this ETF portfolio. XHS has plunged 18% over the past month and carries a Zacks ETF Rank #3 (Hold) with a Medium risk outlook.

: Volume 3.02 Times Average

This media ETF was under the microscope as nearly 22,000 shares moved hands. This compares with an average trading volume of roughly 7,000 shares and came as PBS jumped 2.2% in the last trading session.

The movement can largely be blamed on the release of the final two episodes of the latest season of Stranger Things. The show has become the second ever to surpass a billion hours viewed, attracting total viewership of more than 1.15 billion hours in its first 28 days of release. PBS has plunged 31.8% in a month’s time and has a Zacks ETF Rank #3.