Abstract: An evolution of the margin risks was performed using the relationship between excess price yield, prices of margin and conditional volatility. The analysis was performed with GARCH-M model using 21 years of monthly sale price data. The model parameters were estimated using a maximum likelihood function. The sample period ranged from January 1986 to March 2007. A recursive estimation model was used to obtain a temporary evolution of coefficients in a remuneration scheme for risk (CRR). The results revealed the sensitivity of risk-based cost pricing to retail prices (margin).