In the last trading session, Wall Street was generally flat ahead of the busiest week of corporate earnings and the Fed decision. Among the top ETFs, (SPY Quick QuoteSPY - Free Report) gained 0.1% and (DIA Quick QuoteDIA - Free Report) rose 0.32%, while (QQQ Quick QuoteQQQ - Free Report) moved 0.6% 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.

(IJJ Quick QuoteIJJ - Free Report) : Volume 5.76 Times Average

This mid-cap ETF was in the spotlight as around 4.2 million shares moved hands compared with an average of 762,000 shares a day. We also saw some price movement as IJJ gained 0.8% in the last session.

The move was largely the result of heightened volatility that could have a big impact on mid-cap like the ones we find in this ETF portfolio. While large companies are normally known for stability and the smaller ones for growth, mid caps offer the best of both worlds, simultaneously allowing growth and stability in a portfolio. IJJ has gained 3% over the past month and carries a Zacks ETF Rank #1 (Strong Buy) with a Medium risk outlook.

(SCHR Quick QuoteSCHR - Free Report) : Volume 3.53 Times Average

This Treasury ETF was under the microscope as nearly 10.2 million shares moved hands. This compares with an average trading volume of roughly 2.8 million shares and came as SCHR shed 0.2% in the last trading session.

The movement can largely be blamed on falling yields, which are inversely related with the bond prices. SCHR has gained 1.7% in a month’s time and carries a Zacks ETF Rank #3 (Hold) with a Medium risk outlook.