Many banks suffered huge losses during the 2008 financial crisis due to issuing subprime loans.

subprime 是由前缀 sub-（表示"低于、次于"）和 prime（"优质的、首要的"）组成的复合词。prime loans 指信用评级最高的优质贷款，而 subprime loans 则指信用评级低于标准、风险较高的贷款，即"次级贷款"。