It won't be the US MNCs.
The entire global financial system and international institutions like the IMF, WB, WTO, etc were created by the US at Bretten Woods. It's based on US as central player, and the US dollar as the main trade and reserve currency.
If US economy and US dollar suffer, it'll impact the entire world dramatically because I don't see anything to replace it in the foreseeable future.
Haq's Musings: Yuan to Replace Dollar in World Trade?
