American Funds U.S. Government Securities Fund F-1 

This fund primarily dedicates at least 80% of its total holdings to debt instruments that receive backing or sponsorship from the U.S. government, its associated agencies, or various instrumentalities. These investments include dollar-denominated fixed-income assets like bonds, and their exposure can also be achieved through derivative contracts. Furthermore, the fund is permitted to acquire mortgage-backed securities (MBS) issued by federal bodies, though it's important to note that these particular MBS may not carry the explicit full faith and credit guarantee of the U.S. government.