Now, there's an exchange-traded fund looking to capitalize on millennials' emerging buying power.
"Companies well-positioned to target millennials are those likely to do well," said Bruno del Ama, founder and CEO of Global X Funds, which launched the Global X Millennials Thematic ETF last week.
"It's generally bad to bet against the American consumer. And millennials are increasingly becoming part of the American consumer. In fact, they're the growth engine," he told CNBC's "Squawk Box," saying millennials earn roughly $2 trillion, with projections of income growth to $8 trillion by 2025.