During an Oct. 4, 2011, interview on MSNBC, host Ed Schultz and Sen. Bernie Sanders, I-Vt., discussed the "Occupy Wall Street" protests, which are targeting the financial services sector. Sanders offered a statistic designed to demonstrate the power of American banks.



Sanders suggested that many of the protesters "have not seen the president be as strong as he should be on Wall Street," saying they want the federal government to take tougher measures against financial-services companies.



"Ed, today, you have six financial institutions, the largest six, that have assets that are the equivalent of 60 percent of the GDP of the United States of America," Sanders said. (GDP stands for gross domestic product.)



We wondered whether Sanders’ math was correct.



When we contacted Sanders’ office, a spokesman provided testimony to a congressional oversight panel by Simon Johnson, a professor of entrepreneurship at the MIT Sloan School of

Management. "Our six largest bank holding companies currently have assets valued at just over 63 percent of GDP," Johnson testified, citing figures for the fourth quarter of 2010. "This is up from around 55 percent of GDP before the crisis (e.g., 2006) and no more than 17 percent of GDP in 1995."



We wanted to find the original statistics, and we located them in a chart posted by the National Information Center, the federal repository of data about banks and other institutions for which the Federal Reserve has a supervisory, regulatory or research interest. The chart lists the 50 biggest bank holding companies as of June 30, 2011.



Here are the top six and their total assets:



1. Bank of America Corp., $2.264 trillion

2. J.P. Morgan Chase & Co., $2.246 trillion

3. Citigroup Inc., $1.957 trillion

4. Wells Fargo & Co., $1.260 trillion

5. Goldman Sachs Group Inc., $937 billion

6. Morgan Stanley, $831 billion



Together, the top six companies’ assets were $9.495 trillion.



For the second part of the equation -- gross domestic product -- we turned to the U.S. Commerce Department’s Bureau of Economic Analysis.



Though the time spans don’t line up perfectly, we decided to use the GDP figure for 2010, the most recent full year. That figure is $14.527 trillion.



Dividing these top banks’ assets by the national GDP produces a result of 65 percent -- which is actually a slightly larger percentage than Sanders had indicated, but certainly in the ballpark.



To make sure we weren’t missing something, we contacted a few experts on financial services issues. They offered a few caveats:



• The comparison is a bit of apples vs. oranges. The banks’ asset figures are an aggregation measured at a single point in time, whereas the GDP figure is an aggregation of goods and services measured over time. "This distinction is the equivalent to a comparison of your net worth with your personal income," said Lawrence White, an economist at New York University’s Stern School of Business. "Economists generally don't find these sorts of comparisons very useful or interesting. So the best that can be said is that these comparisons provide a rough sense of comparative magnitudes."



• The data are constantly moving. "Several of these banks, especially Bank of America, have lost significant" value since the figures were published in June 2011, said Satya Thallam, director of the Financial Markets Working Group at George Mason University's Mercatus Center. The denominator, GDP, is always changing, as well. So, any estimate is true for a specific point in time, but possibly out of date not long after it’s made.



• Banks’ overseas holdings significantly complicate the comparison. For starters, the comparison Sanders is making doesn’t mean that these banks own 60 percent of the U.S. wealth, because some of these banks’ assets are in overseas holdings. However, Sanders appears to be on safe ground with his phrasing, since all he said was that the two dollar figures were "equivalent."



Potentially more problematic for Sanders is that the assets-to-GDP ratio for the top six bank companies in the U.S. are actually quite modest when compared to the biggest banks in other nations.



A 2010 study by J.P. Morgan listed the 25 biggest banks internationally in 2008, along with the percentages of their home country’s GDP. The highest was UBS, with 376 percent of Switzerland’s GDP. And six other banks all had assets as large as their home country’s GDP -- Credit Suisse Group of Switzerland (218 percent), Dexia of Belgium (180 percent), Fortis of the Netherlands (155 percent), Royal Bank of Scotland of the United Kingdom (131 percent), Barclays of the United Kingdom (112 percent) and BNP Paribas of France (101 percent).



All of these dwarf the combined holdings of the top six banks in the U.S., in part because America’s GDP is so much larger than the GDP of these other nations.



The significance of this fact for Sanders’ assertion, however, is less clear.



"This doesn't tell us what is a ‘proper’ or ‘appropriate’ number," Thallam said. "One might reply that other countries are much more concentrated, but that only means they're worse -- not that we're in a good position." Some scholars, he added, have said that even at current concentration levels, U.S. banks should be broken up because they create a "too big to fail" problem. "On the other hand, people for years said that banking exhibited economies of scale, so consolidation was natural," Thallam said.



Our ruling



Sanders’ math is correct -- in fact, the percentage he offers is actually a little low. And he’s careful to say only that the banks’ assets are only "equivalent" to 60 percent of the United States’ GDP, not that the banks own 60 percent of the United States. Sanders doesn’t note that big banks in other countries are far bigger, compared to their nations’ GDP, than the U.S. banks are. Still, on balance, we rate his statement True.