A test of the Investor's Daily stock ranking system

This paper examines the profitability of trading strategies derived from stock rankings published in Investor's Business Daily. The best system provides market-adjusted abnormal monthly returns of 1.81% from buying S&P 500 stocks, and a 3.18% abnormal return on an arbitrage portfolio. Stocks selected for trading have above average volatility, but a portion of abnormal return may be a reward for identifying stocks with short-run sustainable price momentum. Results seem indicative of market inefficiency, but the phenomena may be temporary since abnormal returns are lower during the second half of the data set.