Trupanion, the nation’s largest pet insurer, long promised that its premiums would go up no more than 20% a year. But it has been telling pet owners in many places that prices are going up by 33% or more. And the problem is, if your pet has a pre-existing condition, no other insurer is going to take you – so your options are to keep paying the premiums or pay your vet out of pocket. Trupanion and other insurers blame rising vet bills. About 5.4 million pet insurance policies are in force in the U.S.