Progressive is a major auto insurer that also sells home, renters and commercial vehicle insurance, built around aggressive direct-to-consumer marketing and usage-based insurance programs that price premiums partly on actual driving behavior. The company was an early mover into selling insurance directly online and by phone rather than exclusively through independent agents, a distribution model that has helped keep its costs lower than insurers relying more heavily on agent commissions. Progressive's Snapshot program, which tracks driving habits through a mobile app or plug-in device, lets safer drivers earn lower premiums and gives the company more granular data to price risk than traditional demographic-based underwriting. Like other insurers, its profitability depends on the combined ratio, the relationship between premiums collected and claims plus expenses paid out, which Progressive has historically managed more tightly than many peers.