A Random Walk Down Wall Street

Malkiel argues that stock prices follow a random walk, meaning that past price movements do not predict future ones, and that no method of security selection or market timing reliably beats a low-cost index fund after costs. The book was first published in 1973 and has been revised repeatedly.

His argument works by elimination. He examines technical analysis and reports that chart patterns have no predictive power once transaction costs are included. He examines fundamental analysis and reports that analyst earnings forecasts are poor and that funds employing analysts do not persistently outperform. He covers the history of speculative bubbles from tulips through the dot-com period and the housing bubble, using them to show that markets can be wrong while remaining impossible to beat systematically.

He presents the efficient market hypothesis in its weak, semi-strong and strong forms, and takes a moderate position, accepting that anomalies exist while arguing that they are too small and too unstable to exploit after costs. Later editions address the behavioural finance challenge and the documented factor premiums, and Malkiel concedes ground while maintaining the practical conclusion.

The final section is a practical guide covering life-cycle allocation, the treatment of bonds, real estate, international exposure and taxes. The efficient market framing has been substantially qualified since 1973, and Shiller's excess volatility work and the factor literature both cut against the strongest version. Malkiel's practical conclusion, that costs are certain and outperformance is not, does not depend on market efficiency and survives the theoretical dispute intact.

Chemical Bank Chairman's Professor of Economics Emeritus, Princeton University; Chief Investment Officer, Wealthfront; former Vanguard director

A Random Walk Down Wall Street, now in its thirteenth edition after fifty years, is the primary popular source for the index-fund case.

Princeton University, Wealthfront