For most rates, each rate filing shall be effective __________ after the rates and supplementary information are filed.

The rate filing procedure in Utah establishes that most rate changes become effective 30 days after the rates and supplementary information have been filed with the appropriate regulatory authority. This timeframe allows for necessary reviews and assessments by both the insurance companies and the regulators to ensure that the rates comply with state laws and are justified based on the underlying data.

Thirty days is a reasonable period for stakeholders to consider the impact of the rate change, which includes evaluating market conditions and any potential effects on policyholders. Furthermore, the regulatory framework is designed to maintain fair competition in the insurance market while also protecting consumers from abrupt changes in premium costs. Thus, the correct answer highlights the importance of this regulatory period in promoting transparency and stability within the insurance market.