The following is the Oct. 18, 2022, Congressional Research Service report, Multiyear Procurement (MYP) and Block Buy Contracting in Defense Acquisition: Background and Issues for Congress.
From the report
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...
https://news.usni.org/2022/10/19/report-to-congress-on-pentagon-block-buy-contracts