SPDR S&P 500, or SPY, is the world’s largest ETF today with about $240 billion in assets, but it wasn’t much to look at when it debuted in 1993. Some days it was on “volume life support,” trading as little as 18,000 shares; there was even talk of pulling the plug. Yet true believers, guerrilla marketing, and a booming 1990s stock market helped the product gain favor. And once SPY took off, the markets were forever changed. This episode also explores how SPY soon inspired a host of other ETFs, from international and sectors to fixed income and gold.