Reporting a stolen car is the responsibility of the car owner or the person in possession of the vehicle at the time of the theft. They should report the theft to the local police department or law enforcement agency.
The financial company may be involved if the car was financed or leased through them. In such cases, the company may have a security interest in the vehicle and may take action to protect its interest, such as repossessing the car or filing a claim with their insurance company. However, reporting the theft to the police is still the responsibility of the car owner or the person in possession of the vehicle.