When a company wants to take over an insurance company, it has to file a Form A Application for Approval of Acquisition with the insurance department of each state where the insurance company does business. The filing is handled by an office within the insurance department usually called something like "Compliance" or "Financial Monitoring."
In most states, the Form A is a confidential filing, Texas being a notable exception (call 512-305-7210 to get Texas Form As).