ChatGPT News-based Forecasts of Stock Market Returns

Are the latest forms of artificial intelligence (AI) better at forecasting stock market returns than humans? In his February 2023 preliminary paper entitled “Surveying Generative AI’s Economic Expectations”, Leland Bybee summarizes results of monthly and quarterly forecasts by a large language model (ChatGPT-3.5) of U.S. stock market returns and 13 economic variables based on samples of Wall Street Journal (WSJ) news articles. He uses the S&P 500 Index as a proxy for the U.S. stock market. He asks ChatGPT to provide reasons for responses. He compares accuracy of ChatGPT forecasts to those from: (1) surveys of humans, including the Survey of Professional Forecasters, the American Association of Individual Investors (AAII) and the Duke CFO Survey; and, (2) a wide range of fundamental and economic predictors tested in past research. Using monthly samples of 300 randomly selected WSJ news articles, results of human surveys and various fundamental/economic data during 1984 through 2021, he finds that:

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