Main article: Liability insurance

Liability insurance is a very broad superset that covers legal claims against the insured. Many types of insurance include an aspect of liability coverage. For example, a homeowner's insurance policy will normally include liability coverage which protects the insured in the event of a claim brought by someone who slips and falls on the property; automobile insurance also includes an aspect of liability insurance that indemnifies against the harm that a crashing car can cause to others' lives, health, or property. The protection offered by a liability insurance policy is twofold: a legal defense in the event of a lawsuit commenced against the policyholder and indemnification (payment on behalf of the insured) with respect to a settlement or court verdict. Liability policies typically cover only the negligence of the insured, and will not apply to results of wilful or intentional acts by the insured.

The subprime mortgage crisis
 was the source of many liability insurance losses

  • Public liability insurance or general liability insurance covers a business or organization against claims should its operations injure a member of the public or damage their property in some way.
  • Directors and officers liability insurance (D&O) protects an organization (usually a corporation) from costs associated with litigation resulting from errors made by directors and officers for which they are liable.
  • Environmental liability or environmental impairment insurance protects the insured from bodily injury, property damage and cleanup costs as a result of the dispersal, release or escape of pollutants.
  • Errors and omissions insurance (E&O) is business liability insurance for professionals such as insurance agents, real estate agents and brokers, architects, third-party administrators (TPAs) and other business professionals.
  • Prize indemnity insurance protects the insured from giving away a large prize at a specific event. Examples would include offering prizes to contestants who can make a half-court shot at a basketball game, or a hole-in-one at a golf tournament.
  • Professional liability insurance, also called professional indemnity insurance (PI), protects insured professionals such as architectural corporations and medical practitioners against potential negligence claims made by their patients/clients. Professional liability insurance may take on different names depending on the profession. For example, professional liability insurance in reference to the medical profession may be called medical malpractice insurance.
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), "umbrella" insurance policies (excess insurance that in some circumstances could provide coverage that is broader than the underlying insurance), and "surplus lines" insurance (policies written by non-admitted carriers)