Discipline: Economics
Dating back to work on the random walk hypothesis by French economist Louis Bachelier (1870-1946), efficient market hypothesis asserts that stock market prices are the best available estimates of the real value of shares since the market has taken account of all available information on an individual stock.
Also see: adaptive expectations, rational expectations theory
Source:
H Roberts, 'Stock Market "Patterns" and Financial Analysis: Methodological Suggestions', Journal of Finance, 14, 1 (March, 1959), 1-10