The first life insurance policies were taken out in the early 18th century. The first company to offer life insurance was the Amicable Society for a Perpetual Assurance Office, founded in London in 1706 by William Talbot and Sir Thomas Allen.[7][8] Edward Rowe Mores established the Society for Equitable Assurances on Lives and Survivorship in 1762.
Separate insurance contracts (i.e., insurance policies not bundled with loans or other kinds of contracts) were invented in Genoa in the 14th century, as were insurance pools backed by pledges of landed estates. The first known insurance contract dates from Genoa in 1347, and in the next century maritime insurance developed widely and premiums were intuitively varied with risks.[3] These new insurance contracts allowed insurance to be separated from investment, a separation of roles that first proved useful in marine insurance.

In the United Kingdom, The Crown (which, for practical purposes, meant the civil service) did not insure property such as government buildings. If a government building was damaged, the cost of repair would be met from public funds because, in the long run, this was cheaper than paying insurance premiums. Since many UK government buildings have been sold to property companies and rented back, this arrangement is now less common and may have disappeared altogether.
Formal self-insurance is the deliberate decision to pay for otherwise insurable losses out of one's own money.[citation needed] This can be done on a formal basis by establishing a separate fund into which funds are deposited on a periodic basis, or by simply forgoing the purchase of available insurance and paying out-of-pocket. Self-insurance is usually used to pay for high-frequency, low-severity losses. Such losses, if covered by conventional insurance, mean having to pay a premium that includes loadings for the company's general expenses, cost of putting the policy on the books, acquisition expenses, premium taxes, and contingencies. While this is true for all insurance, for small, frequent losses the transaction costs may exceed the benefit of volatility reduction that insurance otherwise affords.[citation needed]

Accidental loss: The event that constitutes the trigger of a claim should be fortuitous, or at least outside the control of the beneficiary of the insurance. The loss should be pure, in the sense that it results from an event for which there is only the opportunity for cost. Events that contain speculative elements such as ordinary business risks or even purchasing a lottery ticket are generally not considered insurable.
Insurance companies earn investment profits on "float". Float, or available reserve, is the amount of money on hand at any given moment that an insurer has collected in insurance premiums but has not paid out in claims. Insurers start investing insurance premiums as soon as they are collected and continue to earn interest or other income on them until claims are paid out. The Association of British Insurers (gathering 400 insurance companies and 94% of UK insurance services) has almost 20% of the investments in the London Stock Exchange.[26] In 2007, U.S. industry profits from float totaled $58 billion. In a 2009 letter to investors, Warren Buffett wrote, "we were paid $2.8 billion to hold our float in 2008."[27]
In the United States, economists and consumer advocates generally consider insurance to be worthwhile for low-probability, catastrophic losses, but not for high-probability, small losses. Because of this, consumers are advised to select high deductibles and to not insure losses which would not cause a disruption in their life. However, consumers have shown a tendency to prefer low deductibles and to prefer to insure relatively high-probability, small losses over low-probability, perhaps due to not understanding or ignoring the low-probability risk. This is associated with reduced purchasing of insurance against low-probability losses, and may result in increased inefficiencies from moral hazard.[56]
Large number of similar exposure units: Since insurance operates through pooling resources, the majority of insurance policies are provided for individual members of large classes, allowing insurers to benefit from the law of large numbers in which predicted losses are similar to the actual losses. Exceptions include Lloyd's of London, which is famous for ensuring the life or health of actors, sports figures, and other famous individuals. However, all exposures will have particular differences, which may lead to different premium rates.
In the United States, the most prevalent form of self-insurance is governmental risk management pools. They are self-funded cooperatives, operating as carriers of coverage for the majority of governmental entities today, such as county governments, municipalities, and school districts. Rather than these entities independently self-insure and risk bankruptcy from a large judgment or catastrophic loss, such governmental entities form a risk pool. Such pools begin their operations by capitalization through member deposits or bond issuance. Coverage (such as general liability, auto liability, professional liability, workers compensation, and property) is offered by the pool to its members, similar to coverage offered by insurance companies. However, self-insured pools offer members lower rates (due to not needing insurance brokers), increased benefits (such as loss prevention services) and subject matter expertise. Of approximately 91,000 distinct governmental entities operating in the United States, 75,000 are members of self-insured pools in various lines of coverage, forming approximately 500 pools. Although a relatively small corner of the insurance market, the annual contributions (self-insured premiums) to such pools have been estimated up to 17 billion dollars annually.[40]
Insurable interest – the insured typically must directly suffer from the loss. Insurable interest must exist whether property insurance or insurance on a person is involved. The concept requires that the insured have a "stake" in the loss or damage to the life or property insured. What that "stake" is will be determined by the kind of insurance involved and the nature of the property ownership or relationship between the persons. The requirement of an insurable interest is what distinguishes insurance from gambling.
Many institutional insurance purchasers buy insurance through an insurance broker. While on the surface it appears the broker represents the buyer (not the insurance company), and typically counsels the buyer on appropriate coverage and policy limitations, in the vast majority of cases a broker's compensation comes in the form of a commission as a percentage of the insurance premium, creating a conflict of interest in that the broker's financial interest is tilted towards encouraging an insured to purchase more insurance than might be necessary at a higher price. A broker generally holds contracts with many insurers, thereby allowing the broker to "shop" the market for the best rates and coverage possible.
Affordable premium: If the likelihood of an insured event is so high, or the cost of the event so large, that the resulting premium is large relative to the amount of protection offered, then it is not likely that the insurance will be purchased, even if on offer. Furthermore, as the accounting profession formally recognizes in financial accounting standards, the premium cannot be so large that there is not a reasonable chance of a significant loss to the insurer. If there is no such chance of loss, then the transaction may have the form of insurance, but not the substance (see the U.S. Financial Accounting Standards Board pronouncement number 113: "Accounting and Reporting for Reinsurance of Short-Duration and Long-Duration Contracts").
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: