internal transfers

Explaining Piketty: inequality and the financial crisis by France Coppola

German, Japanese and - above all - Chinese lending to the US is the so-called "savings glut" that is widely blamed for creating the financial instability that led to the financial crisis. But Piketty argues that this source of capital is tiny compared to that generated by rising inequality WITHIN the US (my emphasis):

"...this internal transfer between social groups (on the order of fifteen points of USnational income) is nearly four times larger than the impressive trade deficit the United States ran in the 2000s (of the order of four points of national income). The comparison is interesting because the enormous trade deficit, which has its counterpart in Chinese, Japanese, and German trade surpluses, has often been described as one of the key contributors to the “global imbalances” that destabilized the US and global financial system in the years leading up to the crisis of 2008. That is quite possible, but it is important to be aware of the fact that the United States’ internal imbalances are four times larger than its global imbalances. 

"So the total amount of capital available for investment in the US at this time was far larger than the imported "savings glut" caused by its trade deficit. And because the US was importing capital, all of that capital had to be invested WITHIN the US***. As I've noted already, the corporate sector was (and is) running a structural surplus. That leaves the household sector and the government sector to absorb the capital. No wonder lenders aggressively targeted those households most in need of money. They had to put that capital somewhere****, and poor households were both the easiest to lend to (because they needed the money) and gave the best returns (because they were the highest risk). Financial innovation enabled far more of this capital than usual to find its way to poorer households: the concentration of risk that would normally have limited individual lenders' exposure to poorer quality borrowers was dispersed across the globe through securitisation and amplified with derivatives.