We analyze the stock prices of the S&P market from 1987 to 2012 with the covariance matrix of the firm returns determined in time windows of several years. The eigenvector belonging to the leading eigenvalue (market) exhibits in its long term time dependence a phase transition with an order...

The problems related to the application of multivariate GARCH models to a market with a large number of stocks are solved by restricting the form of the conditional covariance matrix. It contains one component describing the market and a second simple component to account for the remaining...

The problems related to the application of multivariate GARCH models to a market with a large number of stocks are solved by restricting the form of the conditional covariance matrix. It contains one component describing the market and a second simple component to account for the remaining...

Kirman's ant model has been used to characterize the expectation formation of financial investors who are prone to herding. The model's original version suffers from the problem of N-dependence: its ability to replicate the statistical features of financial returns vanishes once the system size...

Kirman’s “ant model” has been used to characterize the expectation formation of financial investors who are prone to herding. The model’s original version suffers from the problem of N-dependence: its ability to replicate the statistical features of financial returns vanishes once the...