How does the housing bubble debt compare? If you add together mortgages and revolving home equity, then from the first quarter of 1999 to when housing-related debt peaked in the third quarter of 2008, the sum increased from $3.28 trillion to $9.98 trillion. Over this period, housing-related debt had increased threefold. Meanwhile, over the entire period shown on the chart, the balance of student loans grew by more than 6x. The growth of student loans has been twice as steep -- and it's showing no signs of slowing.*

Obviously the number of students didn't grow by 511%. So why are education loans growing so rapidly? One reason could be availability. The government's backing lets credit to students flow very freely. And as the article from yesterday noted, universities are raising tuition aggressively since students are willing to pay more through those loans.

This student loan growth sure looks unsustainable. But it's hard to see how this bubble's inevitable pop might look. Ultimately, it might look more like a balloon slowly deflating, if a large portion of college graduates decide to strategically default on their debt over time.

All this college debt could put the U.S. on a slower growth path in the years to come. As Americans grapple with high student loan payments for the first few decades of their adult lives, they'll have less money to spend and invest. All that money flowing into colleges and universities is being funneled away from other industries where it would have been spent in future years. Of course, this would be a rather unfortunate irony: higher education is supposed to enhance a nation's growth, but with such an enormous debt burden, graduates might not be able to spend and invest enough to allow that growth to occur.

* You might notice that student loan growth was actually flat in the second quarter. The same thing happened in the second quarter of last year, so this is likely a seasonal effect. We should expect growth to resume this quarter.

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