Today, there are more than 1,600 ETFs. From clean energy to private equity to short-term volatility, there's an ETF for nearly every sector and investment strategy.
Some of the best ETFs to buy in 2015 help investors get a piece of a very lucrative trend: mergers and acquisitions.
The collective total of global M&A announced year to date surpassed $1 trillion through the first week of April. At the current pace, M&A activity is on track to exceed $3.7 trillion in 2015.