What would US economy downgrade mean?
The ratings agency Moody's has raised the stakes as the US approaches its debt limit.
The firm has put the world's biggest economy on review for a credit score downgrade if American politicians continue their standoff and fail to raise the $14.3 trillion borrowing cap.
Other agencies have warned they may also act - but Moody's is the first to begin a formal review.
Bronywn Curtis from HSBC explains what this would mean for the US.