The subject of the study for this dissertation is the relationship between pricing and reserving risks for property-casualty insurance companies. Since the risk characteristics of insurers differ based on their structure, objectives and incentives, segmenting the insurers into subgroups would allow for a better understanding of group-specific risks. Based on this approach to analyzing insurer financial risks, we find that, in a given accident year, the pricing and reserving errors are positively correlated, especially in long-tailed lines of business. Large insurers, stock insurers, and multi-state insurers, in general, exhibit a strong correlation between accident-year price and reserve errors. However, only size of insurers appears to be a factor that influences the interaction between price changes and the calendar year loss reserve adjustments. Furthermore, we find that the pricing risk and reserving risk are marginally more homogenous within a market segment when size, type and number of states are employed as criteria for market segmentation, hence insurance regulators should consider the refined market segments for the RBC formula. The empirical results also indicate that, in general, Chain-Ladder reserving method likely contributes to loss reserve errors when there is a change in the loss development pattern and the magnitude of the errors is worse for large insurers. Finally, we find that our proposed measurement method for the product diversification benefit provides support for the notion that the diversification benefit on the incurred losses increases with the number of lines in the portfolio. Yet, the diminishing returns tend to decrease the diversification benefit on the incurred losses for insurers that write the business in more than six of the selected lines. To the contrary, our proposed measure does not provide clear evidence that writing business in many product lines increases the product diversification benefit with respect to adverse loss development. We do find that the diversification benefit for both incurred losses and loss development is higher for larger insurers. Hence, for risk management and regulatory purposes, a stronger case can be made for considering firm size than product diversification.