Which of the following is NOT a factor considered by independent rating services in assessing insurance companies?

Independent rating services assess insurance companies by analyzing various factors that indicate financial stability and the ability to fulfill policyholder obligations. Marketing strategies, while important for a company's overall success, do not directly impact the insurer’s financial health or operational effectiveness in paying claims.

In contrast, prior claims experience provides insight into the insurer's likelihood of future claims and overall risk management. Investment earnings reflect how well an insurer is managing its portfolio to support future claims and obligations. Levels of reserves show the financial preparedness of the company to pay out future claims based on the policies they have in force. These factors are crucial in determining the reliability and stability of an insurance provider.

Marketing strategies are more related to the company's approach to attracting and retaining customers, and they do not serve as a reliable indicator of financial strength or claims-paying ability. Thus, this makes marketing strategies the factor that is not typically considered by independent rating services when assessing insurance companies.