In April, Americans saved almost six percent of GDP; the highest savings rate in over 15 years.
The surge in savings mirrors the US federal deficit. As the government goes deeper into the red, households are building up savings. Americans recognize that today's government deficit is tomorrow's tax hike. Therefore, they are accumulating resources now, to compensate lower future disposible income.
This is why Keynesian fiscal stimulus packages never work. It is a lesson that the clowns down at the UK treasury have forgotton.