During global market panics or dollar shortages, international banking networks can experience severe foreign currency squeezes that threaten domestic market stability. To protect system liquidity, major global central banks maintain Bilateral Swap Line Networks.

Through these arrangements, a foreign central bank deposits a layer of its own currency as collateral with an issuing central bank (such as the Federal Reserve Bank of New York), receiving an equivalent pool of the target foreign currency at prevailing spot rates:

Foreign Central Bank deposits local currency -> Ingests USD from Federal Reserve -> Auctions USD to domestic banks -> Restores global market trading velocity

These swap lines provide non-US central banks with the capacity to inject US dollar liquidity directly into their domestic banking networks during a global liquidity crunch, preventing payment systems from freezing.