With the number of ETF strategies exploding, figuring out which ones are actually worthwhile is growing more complicated than ever. Exchange-traded funds brought in $540 billion in assets in the first half of the year alone, and the sheer number of ETF launches is overcrowding the markets, according to ETF.com president Dave Nadig. This time next year, the number of ETFs in the US could reach 9,000, given the current pace of launches. “That makes everybody’s job really miserable,” he said during a panel a ...