6. iShares MSCI EAFE ETF – EFA

Average Daily Volume: $1.37 billion

EFA is one of the largest ETFs, including stocks from Europe, Australia and the Far East, and it was traded heavily as a bailout plan for the ailing Greek economy inched towards fruition and as monetary policies between the ECB and the Fed diverged. An average of 20 million EFA shares changed hands each day.

5. iPath S&P 500 VIX Short-Term Futures ETN – VXX

Average Daily Volume: $1.46 billion

Traders used the VXX to play third- and fourth-quarter market volatility stemming from uncertainty around U.S. interest rates, commodities and the health of emerging markets. On average, investors traded 56 million VXX shares per day in 2015.

4. iShares MSCI Emerging Markets ETF – EEM

Average Daily Volume: $2.23 billion.

In 2015, the iShares MSCI Emerging Markets ETF lost around 25 percent of its NAV and investors heading to the exits may have pushed the fund’s high trading volume. However, respected analysts such as DoubleLine’s Jeff Gundlach argue that emerging markets may provided the best opportunity to improve future returns, and the fund may attract bargain hunters after pushing through six-year lows. On average, 57 million shares of EEM were traded daily.