Insurance companies don't like risk. Before purchasing or adopting a dog, contact your insurance agent to make sure you can receive coverage under your homeowner's or tenant policy with the particular breed You might need to look for another insurance company, or get a rider, or otherwise pay a higher premium to keep your property insured.
According to a 2012 Forbes article, the riskiest dog breeds for homeowners insurance include the American Staffordshire terrier, or pit bull; Rottweiler; Doberman pinscher; German shepherd; chow chow; Presa Canario; Great Dane; Siberian husky; Alaskan malamute and Akita. Wolf hybrids, crosses between a domestic dog of any type and a wolf, are also difficult to insure. You might also experience problems insuring a mixed-breed dog if one of the parents is considered a risky type.
If you own a dog that's not on the list of risky breeds but already has a history of aggressive behavior, your insurance company might decline to renew your policy or exclude dog bite coverage. If your insurance company ever settled a claim with someone your dog injured, odds are you won't remain covered for that particular canine.