Insurance may also be purchased through an agent. A tied agent, working exclusively with one insurer, represents the insurance company from whom the policyholder buys (while a free agent sells policies of various insurance companies). Just as there is a potential conflict of interest with a broker, an agent has a different type of conflict. Because agents work directly for the insurance company, if there is a claim the agent may advise the client to the benefit of the insurance company. Agents generally cannot offer as broad a range of selection compared to an insurance broker.

Annuities provide a stream of payments and are generally classified as insurance because they are issued by insurance companies, are regulated as insurance, and require the same kinds of actuarial and investment management expertise that life insurance requires. Annuities and pensions that pay a benefit for life are sometimes regarded as insurance against the possibility that a retiree will outlive his or her financial resources. In that sense, they are the complement of life insurance and, from an underwriting perspective, are the mirror image of life insurance.
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.[24] 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.
Often a commercial insured's liability insurance program consists of several layers. The first layer of insurance generally consists of primary insurance, which provides first dollar indemnity for judgments and settlements up to the limits of liability of the primary policy. Generally, primary insurance is subject to a deductible and obligates the insured to defend the insured against lawsuits, which is normally accomplished by assigning counsel to defend the insured. In many instances, a commercial insured may elect to self-insure. Above the primary insurance or self-insured retention, the insured may have one or more layers of excess insurance to provide coverage additional limits of indemnity protection. There are a variety of types of excess insurance, including "stand-alone" excess policies (policies that contain their own terms, conditions, and exclusions), "follow form" excess insurance (policies that follow the terms of the underlying policy except as specifically provided), and "umbrella" insurance policies (excess insurance that in some circumstances could provide coverage that is broader than the underlying insurance).[36]
Methods for transferring or distributing risk were practiced by Chinese and Babylonian traders as long ago as the 3rd and 2nd millennia BC, respectively.[1] Chinese merchants travelling treacherous river rapids would redistribute their wares across many vessels to limit the loss due to any single vessel's capsizing. The Babylonians developed a system which was recorded in the famous Code of Hammurabi, c. 1750 BC, and practiced by early Mediterranean sailing merchants. If a merchant received a loan to fund his shipment, he would pay the lender an additional sum in exchange for the lender's guarantee to cancel the loan should the shipment be stolen, or lost at sea.

In the United States, the underwriting loss of property and casualty insurance companies was $142.3 billion in the five years ending 2003. But overall profit for the same period was $68.4 billion, as the result of float. Some insurance industry insiders, most notably Hank Greenberg, do not believe that it is forever possible to sustain a profit from float without an underwriting profit as well, but this opinion is not universally held. Reliance on float for profit has led some industry experts to call insurance companies "investment companies that raise the money for their investments by selling insurance."[28]

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:
×