The largest companies change over time as subsidiaries are bought and sold and companies liquidate assets to accomplish other goals. With that said, some car insurance companies have achieved such public awareness that they continue to grow and maintain positions near the top of the list. But it should be noted that the largest insurance companies may not be the largest car insurance companies, because some companies, such as State Farm, have a tremendous amount of underwriting power, but limited investments in auto insurance alone.
Esurance is at the top of the auto insurance list, with high financial ratings as well as a huge customer base throughout the country. State Farm is the second highest rated, and hold a similar position among United States insurance companies in general. GEICO, with it's roots in government employee insurance and of the most widely recognized insurance mascots ever is ranked at third, and Allstate insurance is rated by financial institutions as the number four choice.
Keep in mind that largest does not mean best. It simply means that the company has more customers than other companies, or that it is currently rated with a higher financial value. In this way, top-rated companies could be rated differently by using different standards for the criteria. In most situations, using the list provided here, which is based on financial ratings rather than number of customers, provides you with more insight into the long-term viability of the company rather than basing your choice a current television fad that prompted more people to sign up. Insurance is far too important to base on an animated ad, and the best advice to research the company you are considering before you sign an insurance policy.