I'm currently trying to estimate the market price of risk (lambda) in the Vasicek Model, and am running into difficulties.
Using the Excel Solver tool and the Maximum Likelihood Estimation method for the other three parameters (mean, reversion speed, volatility) gave me good results but I'm having difficulties with the market price of risk.
Can I just use Excel Solver again (or re-do) with 4 parameters (instead of the initial 3), or is there another way to transform the real world parameters into risk-neutral parameters?
Thank you in advance