The reason the LLR has this power is that it exploits a collective bias in the implicit assessment of the probability of extreme aggregate events by private agents. We show this result in a context where financial intermediaries understand the risks of their own market, but are uncertain about the risks in other markets. In particular, they fear not being able to collect on their claims if other markets are hit before theirs. In response to this uncertainty, intermediaries demand for other intermediaries to fully collateralize their contingent liabilities, which inefficiently locks scarce collateral assets. The LLR may know less about each market than do intermediaries, but it does know that it is impossible for all intermediaries to come out second in the event of a crisis. This knowledge is enough to leverage the value of a LLR facility, as for any given level of resources pledged by the LLR, intermediaries collectively magnify its value and free collateral accordingly