In the last trading session, U.S. stocks were mixed. Among the top ETFs, investors saw (SPY Quick QuoteSPY - Free Report) gain about 0.2%, (DIA Quick QuoteDIA - Free Report) lose about 0.07% and (QQQ Quick QuoteQQQ - Free Report) move higher by 0.06% 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:

(USD Quick QuoteUSD - Free Report) : Volume 2.99 times average

This ultra semiconductor ETF was in the spotlight yesterday as nearly 14,500 shares moved hands compared with an average of roughly 4,900 shares a day. We also saw some price movement as USD gained nearly 2.8% last session.

The movement can largely be credited to upbeat fundamentals of several semiconductor stocks. USD was up 10% in the past one month.

(TIP Quick QuoteTIP - Free Report) : Volume 2.80 times average

This U.S. TIPS ETF was under the microscope yesterday as more than 3.91 million shares moved hands. This compares with an average trading day of around 1.40 million shares and came as TIP gained about 0.04% in the session. TIP, however, lost about 1.2% in the past one month.

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