One of the main reasons large financial institutions got into so much trouble during the Great Recession was because they took on so much debt, or leverage, that could not be seen on their balance sheets. For instance, the degree of leverage at Lehman Brothers, which ultimately collapsed, was supposedly 31 in 2007, meaning that for every $1 in equity, the company had $31 in debt. Because Lehman had such a small amount of cash set aside for losses or heavy outflows, any material impact to its assets or investments could make the firm insolvent, and that's exactly what happened.
Since then, regulators have created more methodologies to determine how much exposure and debt a bank has in order to ensure that what happened to Lehman Brothers doesn't happen again. As the economy heads into precarious times, it's a good idea to see where the large U.S. banks stand in terms of leverage.
Image source: Goldman Sachs.