An argument is given for individual firm beta instability based upon the stochastic character of the market weights defining the market portfolio and the constancy of its beta. This argument is generalized to market weighted portfolios and the form of the stochastic process generating betas is...

I address the dichotomy between American put option pricing theory and the numerical algorithms designed to estimate American put option prices. The literature has focused only on pricing error. However, early exercise is the essence of American option pricing (exercising) and with it comes the...

The binomial algorithm (Cox and Rubinstein, 1985) is an accepted theoretically justifiable standard for measuring the accuracy of American put option pricing algorithms. An important question is whether it also generates accurate estimates of the early exercise boundary (Lamberton, 1993). I show...