Modern financial markets offer the real world's best approximation to the idealized price auction market envisioned in economic theory. Nevertheless, as the increasingly exquisite and detailed financial data demonstrate, financial markets often fail to behave as they should if trading were truly...

We document a striking change in index return serial dependence across 20 major market indexes covering 15 countries in North America, Europe, and Asia. While many studies found serial dependence to be positive until the 1990s, it switches to negative since the 2000s. This change happens in most...