vem desse paper do Mendonza e Korinek, NBER 19362:
"Assume an Emerging Economy that borrows from abroad subject to a collateral constraint. Since the current account is countercyclical, periods of expansion are also periods of leverage build-up. Hence, if at sufficiently high leverage ratios the collateral constraint becomes binding, it forces agents to reduce their spending, which lowers aggregate demand and leads to declines in the real exchange rate and asset prices. Since the value of collateral is tied to these prices, such declines tighten the collateral constraint and force agents to cut back further on spending, triggering a vicious circle."