The federal tax cut and the increase in federal spending at the beginning of 2018 substantially increased the government deficit, requiring a jump in the amount of new Treasury securities offerings on financial markets to fund the gap. One question is whether the government will have to rely on foreign investors to buy these securities. Data for the first half of 2018 are now available and, so far, the country has not had to increase the pace of borrowing from abroad. The current account balance, which measures how much the United States borrows from the rest of the world, has been essentially unchanged. Instead, the tax cut has boosted business saving, allowing the United States to finance the higher federal government deficit without increasing the amount borrowed from foreign investors.
China lends to the rest of the world because it saves much more than it needs to fund its high level of physical investment spending.
The rise in oil prices from near $30 per barrel in 2000 to around $110 per barrel in mid-2014 was a dramatic reallocation of global income to oil producers.