This is a common scenario. The driver who caused your Massachusetts motor vehicle accident only has $20k in liability protection. But, suppose your damages (medical bills, lost wages, pain and suffering) exceed $20k. In that event you must make an underinsured claim with your auto insurance carrier. The minimum amount you must have in Massachusetts for underinsurance is $20k. But, your underinsurance coverage only kicks in if it exceeds the amount of the liability policy limits of the at-fault driver. Therefore, purchase as much underinsurance coverage as you can afford. It can make a world of difference and protects you when you most need it.