The shadow banking system is complex, because it comprises a mix of institutions and vehicles.&nbsp;Investment funds other than MMFs account for 29% of total, and SIVs make up 9%, but the shadow system also includes public financial institutions (such as the government-backed mortgage lender Fannie Mae in the US). They are some of the largest counterparties with the regular banking system, and their combined credit creation and proprietary trading and hedging may account for much of the global liquidity flows that make monetary and financial stability so difficult to ensure.
影子银行体系很复杂，因为它是各式各样机构和实体的混合体。除货币市场基金之外的投资基金大约占总量的29%，SIV占9%，但影子银行体系还包括公共金融机构（比如美国市场上的政府支持按揭贷款商房利美）。它们是常规银行体系的最大交易对手，它们的信用创造和自营交易及对冲总量占全球流动性流动量的大头，而后者正是货币和金融稳定性难以得到保证的原因。