"Adjustment" (discount) refers to the portion of your bill that your hospital or doctor has agreed not to charge. Insurance companies pay hospital charges at discounted rate. The amount of the discount is specific to each insurance company. When the insurance company pays their portion, the discounted amount (adjustment) is taken off to show the true amount due from the patient (co-insurance). For example, a hospital may charge $10,000 for a surgery that your insurance has agreed to only pay $2,500. Of that $2,500, the patient would have to pay $500 if the patient's responsibility is 20%. After the insurance pays $2,000 and patient pays $500, the remaining $7,500 would be the adjustment.