Large liquidation of synthetic ETFs in periods of higher counterparty risk could force to sell the collateral, often illiquid assets.

大清算合成etf的交易对手风险较高的时期，可以强制出售抵押品，往往是流动性不足的资产。

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Bagehot advised the Bank of England to lend freely to illiquid but solvent banks against good collateral, at a penal rate.

ECONOMIST: Central banks have played a starring role

Some of that collateral, now mostly asset-backed securities, is so illiquid that it has yet to be unwound.

FORBES: Money & Investing