At the most basic level, initial ratemaking involves looking at the frequency and severity of insured perils and the expected average payout resulting from these perils. Thereafter an insurance company will collect historical loss data, bring the loss data to present value, and compare these prior losses to the premium collected in order to assess rate adequacy. Loss ratios and expense loads are also used. Rating for different risk characteristics involves at the most basic level comparing the losses with "loss relativities"—a policy with twice as many losses would therefore be charged twice as much. More complex multivariate analyses are sometimes used when multiple characteristics are involved and a univariate analysis could produce confounded results. Other statistical methods may be used in assessing the probability of future losses.
Property insurance as we know it today can be traced to the Great Fire of London, which in 1666 devoured more than 13,000 houses. The devastating effects of the fire converted the development of insurance "from a matter of convenience into one of urgency, a change of opinion reflected in Sir Christopher Wren's inclusion of a site for 'the Insurance Office' in his new plan for London in 1667." A number of attempted fire insurance schemes came to nothing, but in 1681, economist Nicholas Barbon and eleven associates established the first fire insurance company, the "Insurance Office for Houses," at the back of the Royal Exchange to insure brick and frame homes. Initially, 5,000 homes were insured by his Insurance Office.
Insurers will often use insurance agents to initially market or underwrite their customers. Agents can be captive, meaning they write only for one company, or independent, meaning that they can issue policies from several companies. The existence and success of companies using insurance agents is likely due to improved and personalized service. Companies also use Broking firms, Banks and other corporate entities (like Self Help Groups, Microfinance Institutions, NGOs, etc.) to market their products.
NerdWallet averaged rates for 40-year-old men and women for 20 ZIP codes in each state and Washington, D.C., from the largest insurers, up to 12 in each state. “Good drivers” had no moving violations on record and credit in the “good” tier as reported to each insurer. For the other two driver profiles, we changed the credit tier to “poor” or added one at-fault accident, keeping everything else the same. Sample drivers had the following coverage limits: