It is well known that Banks engage in fractional-reserve lending, meaning that bankers use their deposits in lending operations, with only a part of their loans covered by money reserves.

众所周知，银行采用部分准备金制度，这意味着银行家可以使用存款进行借贷活动，但是这些贷款却只有部分得到了真正货币储备的担保。

youdao

Thus the bank is holding only a fraction of deposits in reserves and is lending out the rest: fractional reserve banking which is what we call the system.

FORBES: What Caused The Great Financial Crash: Gary Gorton Is Right