>> sp500.csv
800 observations of 500 stocks from S&P500. Missing values have been handled.
Taken from the Google Finance service: http://www.google.com/finance/

>> sp500-ret.csv
Estimated average return from each stock.

>> sp500-Gnorm.csv
Covariance factor G found by a data matrix normalization.

>> sp500-Gqr.csv
Covariance factor G found by a QR factorization.

>> sp500-Gsvd.csv
Covariance factor G found by a SVD decomposition.

>> sp500-Gchol.csv
Covariance factor G found by a Cholesky factorization.
