The theoretical approach in dealing with the aggregation of information in markets in general, and financial markets in particular considers information as an exogenous element to the system, focusing just on conditions and consequences of the efficient incorporation of information into prices....

We perform a careful spectral analysis of the correlation structures observed in real and financial returns for a large pool of long-lived US corporations, and find that financial returns are characterized by strong collective fluctuations that are absent from real returns. Once the excessive...