Deficits, while nothing new, add up over time. And while they declined each year from 2011 through 2015, both overall and as a percentage of gross domestic product, the gap has widened again under President Donald Trump. Put it all together, and the amount of U.S. Treasury securities outstanding has roughly tripled since the financial crisis:
https://www.bloomberg.com/opinion/articles/2019-09-26/repo-meltdown-shows-budget-deficit-has-limits
