Alfred Cowles' (1934) test of the Dow Theory apparently provided strong evidence against the ability of Wall Street's most famous chartist to forecast the stock market. In this paper, we review Cowles' evidence and find that it supports the contrary conclusion -- that the Dow Theory, as applied...

In this paper we examine the portfolios of more than 40,000 equity investment accounts from a large discount brokerage during a six year period (1991-96) in recent U.S. capital market history. Using the historical performance for the equities in these accounts, we find that a vast majority of...

Alfred Cowles' (1934) test of the Dow Theory apparently provided strong evidence against the ability of Wall Street's most famous chartist to forecast the stock market. In this paper, we review Cowles' evidence and find that it supports the contrary conclusion -- that the Dow Theory, as applied...

This study shows that U.S. individual investors hold under-diversified portfolios, where the level of under-diversification is greater among younger, low-income, less-educated, and less-sophisticated investors. The level of under-diversification is also correlated with investment choices that...

In this paper, we examine if the diversification decisions of individual investors influence asset prices. First, we show that a vast majority of individual investors in our sample are under-diversified and the unexpectedly high idiosyncratic risk in their portfolios results in a welfare loss -...