In relation to the premium, costs that alter depending on the nature of each risk are known as?

The term that accurately describes costs that change depending on the nature of each risk is "variable expenses." This classification reflects expenses that are not fixed and can fluctuate with the level of risk or specific circumstances surrounding a particular insurance policy. For example, in the context of underwriting, variable expenses might include commissions or other fees that might vary in relation to the amount of coverage provided or the risk exposure identified during the assessment.

While other terms such as "calculated expenses," "fluctuating expenses," and "proportioned expenses" may imply some aspects of cost variability, they do not encapsulate the concept as effectively as "variable expenses." These other terms may suggest a fixed relationship or a method of allocation, which does not accurately convey the essence of costs that directly correlate with changing risk factors. Therefore, identifying these costs as variable expenses provides clarity in understanding their impact on underwriting and the final premium calculation.