The economics of conditional heteroskedasticity: Evidence from Canadian and U.S. stock and futures markets

This paper provides insight into the sources of time variation and persistence in volatility by presenting new evidence concerning the price behavior of three index futures contracts and associated stock price indexes (the New York Stock Exchange Composite index, Standard and Poor's 500 index, and Toronto 35 index). Although persistence in the second moments of stock returns distribution is widely documented, the economic explanation for generalized autoregressive conditional heteroskedasticity is not established. Cross-sectional differences in measured persistence indicate that market characteristics thought to impede information flows may not play a significant role in explaining generalized autoregressive conditional heteroskedasticity effects.