Securities Law Commons^™

Do Individual Investors Affect Share Price Accuracy? Some Preliminary Evidence, Alicia Davis Evans

Law & Economics Working Papers Archive: 2003-2009

A common belief is that individual investors are noise traders that distort stock prices. Because accurate share prices are important for economic functioning, the market effect of retail investors has significant regulatory implications. This paper, employing a new NYSE retail trading data set and the R2 metric of share price informedness, contributes to the debate by demonstrating that as the proportion of trading by individual investors increases, the R2 of firms decreases. Adherents of the R2 methodology hold that lower R2's imply more accurate stock prices. The results of an instrumental variable estimation suggest that this relationship is a causal …