RT Journal Article SR Electronic T1 The Myth of 1926: How Much Do We Know About Long-Term Returns on U.S. Stocks? JF The Journal of Investing FD Institutional Investor Journals SP 96 OP 106 DO 10.3905/JOI.2009.18.4.096 VO 18 IS 4 A1 Edward F McQuarrie YR 2009 UL https://pm-research.com/content/18/4/96.abstract AB Investors are often told that the long-term return on U.S. stocks is a known quantity. Few realize that virtually all such statements are based on a data set that begins in 1926, and that because stock trading in the United States is much older, this dataset excludes more than half the total trading record. Even post-1926, certain types of stocks were systematically excluded, up until very recently. This article chronicles the biases and limitations of the post-1926 CRSP-Ibbotson dataset, and explains how these biases limit what is presently known about long-term returns on U.S. stocks.TOPICS: Performance measurement, exchanges/markets/clearinghouses, information providers/credit ratings