American stock market development and performance, 1871–1929

The American stock market played a central role in the allocation of investment funds during the late 19th and early 20th centuries. During the same period the market underwent profound institutional change. Tests of market efficiency are employed to characterize the market's performance, and to ascertain what specific institutional features affected that performance. The market receives mixed reviews. At no time was evidence of substantial market inefficiency apparent. However, money market instability before World War I, and the absence of federal regulation after 1900 did cause stock prices to wander modestly from their “efficient market” values. In both cases intervention by the federal government appears to have improved market performance.