Maximum amount a nonparticipating physician may legally charge a Medicare patient for services billed on nonassigned insurance claims. In the original Medicare plan, it is usually the highest amount of money a beneficiary can be charged for a covered service by doctors and other health care suppliers who do not accept assignment. The limiting charge is 15% over Medicare’s approved amount. The limiting charge only applies to certain services and does not apply to supplies or equipment. This was previously called a maximum allowable actual charge (MAAC) . Also referred to as billing limit or limiting fee charge .