Exchange-traded funds have become vital to investors, offering the ability to build a diversified portfolio through a pooled fund investment while also keeping the flexibility of being able to trade shares whenever the stock market is open. Vanguard Group has developed its own set of ETFs, working in line with its well-established reputation for seeking to minimize the costs of its fund offerings to shareholders. 2017 has been a good year for the markets overall, but a few of Vanguard’s ETFs have stood out for offering stellar returns so far this year.