In the last few years almost 200 specialized 'thematic' ETFs and mutual funds have been created. The asset growth of thematic funds quadrupled. Thematic funds offer unique, tactical bets on investment opportunities grouped by a subject or motif. Typically, it’s about technology and our changing future. Thematic funds tend to be a bull market phenomenon, possibly a result of investor overconfidence and enthusiasm. (There’s a good line that bull markets make everyone look smart.) It’s an intuitive strategy: “Let’s invest in a handful of really smart innovative companies that people are excited about, the growth potential is incredible.”