How is the 340B ceiling price calculated?

Pursuant to Section 340B(a)(1) of the Public Health Service Act and the 340B Ceiling Price and Civil Monetary Penalty final rule (82 FR 1210, January 5, 2017), the 340B ceiling price for a covered outpatient drug is equal to the Average Manufacturer Price (AMP) from the preceding calendar quarter for the smallest unit of measure minus the Unit Rebate Amount (URA). The 340B ceiling price is calculated using six decimal places and HRSA publishes the price rounded to two decimal places.