From the FT:
Investors
such as Fidelity and other money funds are already voting with their
feet. Yields for bills that mature in October and November have risen
above 30 basis points – a level not seen since late 2008, when the
Federal Reserve adopted a zero interest rate policy during the depths of
the financial crisis.
.....
CDS
on US government debt has doubled in the past month and trading volumes
have jumped as a growing number of investors have bought the
instruments, seeking protection against a potential default or making
bets on subtle movements in the derivatives.
If someone is telling you there won't be an impact, they're wrong as one already exists.