Martin Zweig

Martin Zweig was a market analyst, commentator, and fund manager who developed a systematic approach to analyzing market risk based on monetary conditions and market breadth. He is credited with coining the investment rule "Don't fight the Fed" — the principle that when the Federal Reserve is raising interest rates, investors should be cautious about equity markets. He also coined "Don't fight the tape" — the principle of following market momentum. He became famous when he appeared on the PBS program "Wall Street Week" just days before the October 1987 crash and predicted a market decline, which occurred the following Monday in the single worst percentage drop in US stock market history. His book "Winning on Wall Street" (1986) laid out his full analytical framework for measuring market risk through monetary indicators, market breadth statistics, and momentum metrics, providing a quantifiable approach to market timing that influenced a generation of systematic equity analysts. He managed the Zweig Fund and several other closed-end investment vehicles.