Sen. Sherrod Brown of Ohio is pushing a proposal to cap the sizes of large banks. He appeared on ABC News' This Week with Jake Tapper to talk about that, as well as Democratic efforts to pass financial reform.



"Let me give you one statistic, if I could, Jake," Brown said. "Fifteen years ago, the assets of the six largest banks in this country totaled 17 percent of GDP, 17 percent of GDP. The assets of the six largest banks in the United States today total 63 percent of GDP. ... We've got to deal with risk to be sure, but we've got to deal with the size of these banks, because if one of these banks is in serious trouble, it will have such a ripple effect on the whole economy. So we simply can't let them get this big and have this kind of economic power over Main Street, over a small business in Canton, Ohio, or a worker -- a manufacturing plant in Dayton. I mean, we just can't let this happen."



Some very smart people disagree on Brown's point that big banks resist regulation by reason of their sheer mass.



People like Simon Johnson, the former chief economist of the International Monetary Fund, urge measures that would limit the size of the biggest banks. Meanwhile, people like Paul Krugman, the Nobel Prize-winning New York Times columnist, say that breaking up the banks isn't necessary to avert the next meltdown if the proper regulations are put in place.



We were interested in Brown's statistic though: That 15 years ago the top six banks' assets totaled 17 percent of GDP, while today that's 63 percent.



Brown's staff said he got the numbers from 13 Bankers: The Wall Street Takeover and the Next Financial Meltdown, a book by Johnson and James Kwak, that describes the financial crisis and advocates steps for reform, including limits on the size of banks. Johnson also cited the number in an article in the New Republic, co-written with Peter Boone, that criticized President Barack Obama for not pushing rules that are tougher on big banks.



The numbers are a fairly straightforward calculation. You take the bank's total assets, such as loans, cash and securities. (Remember that to banks, a loan is an asset, since they make money off loans.) Then you divide by GDP, which is gross domestic product, and is the total economic output for a country during a given year. Last year, the U.S. gross domestic product was $14.3 trillion.



Johnson's book lists the six biggest banks of 2009 as Bank of America, JPMorgan Chase, Citigroup, Wells Fargo, Goldman Sachs and Morgan Stanley.



The numbers in the book looked right to us, but we wanted to find an outside expert to confirm it. Researchers at the Federal Reserve Bank of Philadelphia agreed to run the numbers to see if they got the same thing.



Sure enough, they found the same thing. The figures were off by a few percentage points because the researchers were able to use numbers from the fourth quarter of 2009 and compared them with the same quarter in 1994. Johnson's book cites numbers from the third quarter.



Here's the information the Federal Reserve Bank of Philadelphia sent us:



Assets (in billions), Dec. 31, 2009

Bank of America Corp. - 2,224.5

JP Morgan Chase - 2,032.0

Citigroup - 1,856.6

Wells Fargo - 1,243.6

Goldman Sachs - 849.3

Morgan Stanley - 771.5

Total 8,977.5

Nominal GDP 14.453.8

Percentage 62.1%



Assets (in billions), Dec. 31, 1994

Citicorp - 250.5

BankAmerica Corp. - 215.5

Chemical Banking Corp. - 171.4

Nationsbank Corp. - 169.6

JP Morgan - 154.9

Chase Manhattan - 114.0

Total 1,075.9

Nominal GDP 7,248.2

Percentage 14.8%



A couple of experts we asked about these numbers noted that Goldman Sachs and Morgan Stanley were for years categorized as investment banks, and would not have been counted in the 1994 numbers. That changed in 2008 at the height of the financial crisis, when the two firms became bank holding companies so they could borrow from the Federal Reserve. The underlying point, though -- that there has been significant consolidation in the banking industry -- remains true, they said.



Brown said, "Fifteen years ago, the assets of the six largest banks in this country totaled 17 percent of GDP ... The assets of the six largest banks in the United States today total 63 percent of GDP." Independent sources and experts confirm that, so we rate his statement True.