Citigroup says:

Leveraged economies, like the U.S., should also be avoided, in favor of emerging market countries, which have reduced borrowing, the bank advised.
With less capital sloshing around the world, and the dollar falling, the U.S. may have to compete more to finance its deficits.
"The U.S. shows up as the world's greatest consumer of external capital," Citi noted. So it "has the most to lose as this capital becomes less freely available

What this is saying is because the US is so much in debt that it shouldn't be loaned anymore money or invested in.

That is one scary advisement in my opinion.