Multiyear Procurement (MYP) and Block Buy Contracting in Defense Acquisition: Background and Issues for Congress [Updated June 6, 2019] [open pdf - 1MB]
From the Summary: "Multiyear procurement (MYP) and block buy contracting (BBC) are special contracting mechanisms that Congress permits the Department of Defense (DOD) to use for a limited number of defense acquisition programs. Compared to the standard or default approach of annual contracting, MYP and BBC have the potential for reducing weapon procurement costs by a few or several percent. [...] Potential issues for Congress concerning MYP and BBC include whether to use MYP and BBC in the future more frequently, less frequently, or about as frequently as they are currently used; whether to create a permanent statute to govern the use of BBC, analogous to the permanent statute that governs the use of MYP; and whether the Coast Guard should begin making use of MYP and BBC."
CRS Report for Congress, R41909
Congressional Research Service: https://crsreports.congress.gov/