The Inspector General of the US Office of Personnel Management (OPM) published its final audit report of Express Script’s (ESI’s) management of the pharmacy benefit of the American Postal Workers Union (the Carrier) Health Plan for contract years 2016 through 2021. The audit found that ESI overcharged the Carrier and the Federal Employee Health Benefits Program (FEHBP) nearly $44.9 million by not passing through all prescription drug discounts and credits required under the Carrier’s contract with OPM. The key findings of the audit that require ESI’s corrective action included: