With few exceptions, most Exchange Traded Funds (ETFs) have done very well so far in 2019. For investors who took advantage of the opportunity in ETFs that follow the S&P 500 or similar large-cap stock indexes, this has rung especially true.

As I mentioned, ETFs that track large capitalization stocks like the S&P 500 or Dow Jones Industrial Average have done the best so far in 2019. The ETF that experienced the most growth in total investors was the Vanguard S&P 500 ETF (VOO) that saw investors place another $6.5 billion in the fund over the last 4 months.

Tracking right behind large-cap stock ETFs were those that invest in the stocks of emerging markets (EM) like Brazil, Russia, China and India. This is a little surprising, because investors are still concerned about trade disputes and tariff wars between the U.S. and China. But because EM funds are considered riskier than large cap funds, investors like the fact that they have been rising together. The correlation between risky and "safe" stock funds indicates that there is more strength behind the bull market than if large cap funds had been rising alone.

Adding a little more confidence to the rally is the group of ETFs representing corporate bonds. The outperformance of this group is a little less surprising than EM because investors have been very attracted to the relatively high dividends paid by these ETFs. For example, if you include the value of its dividends, the iShares High Yield Corporate Bond ETF (HYG) is up almost 8.5% this year, which is very good for a bond fund. For comparison, the Bloomberg Barclay's Aggregate Index, which tracks the performance of corporate bonds in the U.S. is only up 2.5% for the year.