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.
Large loss: The size of the loss must be meaningful from the perspective of the insured. Insurance premiums need to cover both the expected cost of losses, plus the cost of issuing and administering the policy, adjusting losses, and supplying the capital needed to reasonably assure that the insurer will be able to pay claims. For small losses, these latter costs may be several times the size of the expected cost of losses. There is hardly any point in paying such costs unless the protection offered has real value to a buyer.
Crop insurance may be purchased by farmers to reduce or manage various risks associated with growing crops. Such risks include crop loss or damage caused by weather, hail, drought, frost damage, insects, or disease.[33] Index-based insurance uses models of how climate extremes affect crop production to define certain climate triggers that if surpassed have high probabilities of causing substantial crop loss. When harvest losses occur associated with exceeding the climate trigger threshold, the index-insured farmer is entitled to a compensation payment.[34]
Defense Base Act (DBA) insurance provides coverage for civilian workers hired by the government to perform contracts outside the United States and Canada. DBA is required for all U.S. citizens, U.S. residents, U.S. Green Card holders, and all employees or subcontractors hired on overseas government contracts. Depending on the country, foreign nationals must also be covered under DBA. This coverage typically includes expenses related to medical treatment and loss of wages, as well as disability and death benefits.

Retrospectively rated insurance is a method of establishing a premium on large commercial accounts. The final premium is based on the insured's actual loss experience during the policy term, sometimes subject to a minimum and maximum premium, with the final premium determined by a formula. Under this plan, the current year's premium is based partially (or wholly) on the current year's losses, although the premium adjustments may take months or years beyond the current year's expiration date. The rating formula is guaranteed in the insurance contract. Formula: retrospective premium = converted loss + basic premium × tax multiplier. Numerous variations of this formula have been developed and are in use.
NerdWallet compared quotes from these insurers in ZIP codes across the country. Rates are for policies that include liability, collision, comprehensive, and uninsured/underinsured motorist coverages, as well as any other coverage required in each state. Our “good driver” profile is a 40-year-old with no moving violations and credit in the “good” tier.