"This paper uses monthly returns from 1802-2010, daily returns from 1885-2010, and intraday returns from 1982-2010 in the United States to show how stock volatility has changed over time. It also uses various measures of volatility implied by option prices to infer what the market was expecting...

The recent volatility of stock prices has caused many people to conclude that investors have become irrational in valuing at least some stocks. This paper investigates the behavior of the volatility of stocks on the Nasdaq, which tend to be smaller companies with more growth options, in relation...