In the last trading session, U.S. stocks ended in the green, as investors expected U.K. to choose to remain in the EU. Among the top ETFs, investors saw SPY gain 1.30%, DIA move higher 1.26% and QQQ rise 1.43% 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:

FXB: Volume 9.33 times average

This British currency ETF was in focus yesterday as roughly 283,000 shares moved hands compared to an average of roughly 30,000 shares. We also saw some stock price movement as shares of FXB gained about 1.3% yesterday.

The movement can largely be credited to the ongoing speculation yesterday on whether Britain will stay in the European Union or leave it. FXB was up over 2.7% in the past one-month period. The fund currently has a Zacks ETF Rank #3 (Hold).

TMF: Volume 5.89 times average

This leveraged long-term government bond ETF was in focus on Friday as almost 383,000 shares moved hands. This compares to an average trading day of 138,000 shares. TMF fell about 3.1% in the session.

The movement can largely be attributed to a rise in long-term treasury yields. Funds with leveraged factor tacked on them provide outsized returns in a very short period of time. TMF was up over 4.8% in the past one-month period.