Each year plan sponsors need to assess which formulary option best fits their organization’s financial and clinical goals. Current pharmacy benefit manager (PBM) options include a standard “off-the-shelf” formulary, a custom formulary, or a partially customized formulary. This white paper covers these three options in detail. The paper part of a series on best practices in working with pharmacy benefit managers, with the aim of helping plan sponsors evaluate the formulary options that best matches up with their plan needs.