collateral goods
Goods used as security or backing for a transaction or obligation. This is a technical term, likely encountered in business or legal contexts.
As a condition for the loan, the provision of collateral goods was required.
担保 is the general term for collateral or security, while 裏付け物資 specifically refers to physical goods used as backing.
Compound of 裏付け (backing, support) and 物資 (goods, materials).