Earlier this week, we looked at who has accumulated the biggest piles of debt issued by the U.S. federal government. But which of these players do you suppose is loaning the U.S. government the most money today?

Political Calculations found some surprising results:

Even though the Federal Reserve has been reducing its purchases of U.S. government-issued debt securities since the beginning of 2014, as of 28 May 2014, it has boosted its net holdings of the federal government’s liabilities by $148.8 billion. Meanwhile, the U.S. federal government borrowed an additional $138.1 billion from 1 January 2014 through 28 May 2014.

Or rather, the Federal Reserve has acquired 107.7% of the net new debt that has been issued by the U.S. Treasury and other federal government agencies during the first five months of 2014.

That’s possible because of two factors. First, with the bills for U.S. federal income taxes coming due on 15 April 2014, the federal government experiences a surge of tax revenue during this part of the year, which can be enough to allow it to run a short-term surplus, reducing its need to borrow money during this period of time.

Second, the Federal Reserve is displacing other entities that lend money to the U.S. government, who are seeing their share of debt issued by the U.S. government fall as the debt they hold matures. That allows the U.S. Treasury to roll over a portion of the existing national debt and borrow more money, in this case, from the Fed, which doesn’t show up as a net increase in the overall size of the national debt.

And that is how the U.S. Federal Reserve can lend more money to the U.S. federal government than the U.S. government appears to have borrowed, even as the Fed is reducing the amount it lends to the government!

What do you say we rename the U.S. Federal Reserve to something more catchy like the “Iron Bank of Braavos“?

And when do you suppose that the Iron Bank will have its due?