Open any financial publication and you'll see ads for investment products: exchange-traded funds, mutual funds, and the like. Those ads can tell you a lot about what investors are currently thinking and feeling about the market. But did you ever wonder how Wall Street came to be advertising these prepackaged products? On this edition of the Odd Lots podcast, we speak with Eric Weiner, who leads ETF coverage at Bloomberg and also wrote a book on the history of Wall Street. We talk about the first ever modern advertisement for market investing, a 1948 ad in the New York Times, and how Charles Merrill applied grocery store economics to financial brokerages.