Mikael Gunnarsson, presenterar sitt examensarbete Call Option Pricing in the Regime Swithching Lévy Market Abstract The need for models which can calibrate market prices of options has been one of the main thrusts behind the generalization of the Black-Scholes model. In this master's thesis Lévy processes and hidden Markov models are combined into two different regime switching Lévy markets, the regime switching Black-Scholes market and the regime switching NIG market. These two markets are estimated from stock and stock index data and after having developed a pricing method for call options they are calibrated to market prices of and stock index call options. Both the regime switching Black-Scholes market and the regime switching NIG market seem promising with regard to call option pricing, but further research is needed to draw any universal conclusions.