5 Cents Military Payment Certificate

Series 681 MPC was the last series issued before the August 1969 "conversion day," when all in-theater personnel in Vietnam were required to exchange their current certificates for Series 692 within a single day. The operation was a deliberate counter to black-market currency trading, particularly the practice of Vietnamese civilians and unauthorized personnel holding MPC — on conversion day, anyone not entitled to hold MPC was simply left with worthless paper. Series 681 notes that survived unconverted are typically those held by civilians who couldn't legally exchange them.

The 5-cent denomination existed primarily for PX transactions and was rarely accumulated in large quantities, which ironically makes high-grade survivors somewhat harder to locate than higher denominations.