Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Terrorism insurance is insurance purchased by property owners to cover their potential losses and liabilities that might occur due to terrorist activities. It is considered to be a difficult product for insurance companies, as the odds of terrorist attacks are very difficult to predict and the potential liability enormous. For example the September 11, 2001 attacks resulted in an estimated $31.7 billion loss. This combination of uncertainty and potentially huge losses makes the setting of premiums a difficult matter. Most insurance companies therefore exclude terrorism from coverage in Casualty and Property insurance, or else require endorsements to provide coverage.