The “Fama–French model” is a Nobel laureate-designed tool for predicting the stock market. It guides hundreds of billions in investments. The problem? Its numbers keep shifting. For this Money Talks, Felix Salmon chats with Planet Money host Mary Childs about her deep dive for Bloomberg into finance mathematics. They question the nature of investing, markets, and reality itself.

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Podcast production by Jared Downing and Cheyna Roth.

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