Which scenario does not require a certificate of authority for an insurer?

The scenario that does not require a certificate of authority for an insurer is the investigation of claims under existing policies. This process involves assessing and managing claims based on insurance coverage that policyholders already have. Since the insurer is not engaging in any new business activities or selling new policies, there is no need for them to obtain a certificate of authority specifically for this activity.

In contrast, transacting new business in another state, setting up new branch offices, and marketing new insurance products involve entering new markets or expanding operations, which typically require a certificate of authority to ensure compliance with state regulations. Thus, claim investigations remain under the existing policy framework without necessitating a new certificate of authority.