  Share prices of financial companies from the S&P 500 list have been modeled
by a linear function of consumer price indices in the USA. The Johansen and
Engle-Granger tests for cointegration both demonstrated the presence of an
equilibrium long-term relation between observed and predicted time series.
Econometrically, the pricing concept is valid. For several companies, share
prices are defined only by CPI readings in the past. Therefore, our empirical
pricing model is a deterministic one. For a few companies, including Lehman
Brothers, AIG, Freddie Mac and Fannie Mae, negative share prices could be
foreseen in May-September 2008. One might interpret the negative share prices
as a sign of approaching bankruptcies.

Statistical Finance