A detailed analysis of correlation between stock returns at high frequency is compared with simple models of random walks. We focus in particular on the dependence of correlations on time scales - the so-called Epps effect. This provides a characterization of stochastic models of stock price...

The impact that informed and uninformed agents have on market prices is crucial for informational issues in financial markets. Informed trades are associated with institutional operators while uninformed trades are executed on behalf of retail investors. Using high-frequency data from Euronext...