Luis Catão and Gian-Maria Milesi-Ferretti examine the links between external liabilities and crises in an IMF working paper. An excerpt from the abstract:

… data spanning 1970-2011, we find that the ratio of net foreign liabilities (NFL) to GDP is a significant crisis predictor, and the more so when it exceeds 50 percent in absolute terms and 20 percent of the country-specific historical mean. This is primarily due to net external debt–the effect of net equity liabilities is weaker and net FDI liabilities seem if anything an offset factor. We also find that: i) breaking down net external debt into its gross asset and liability counterparts does not add significant explanatory power to crisis prediction; ii) the current account is a powerful predictor, either measured unconditionally or as deviations from conventionally estimated “norms”; iii) foreign exchange reserves reduce the likelihood of crisis more than other foreign asset holdings; iv) a parsimonious probit containing those and a handful of other variables has good predictive performance in- and out-of-sample. The latter result stems largely from our focus on external crises stricto sensu.