Here's what's up on Monday's Squawk on the Street:
--Jack Bogle, chairman and founder of the Vanguard Group, will join us minutes after the opening bell rings to tell investors what they need to know following the first-ever downgrade of the U.S. government's top-tier credit rating.
--Former Fed Chief Alan Greenspan says the downgrade means more trouble ahead for financial markets. At 10 a.m. ET, we'll see if two former Federal Reserve Board Governors, Frederic Mishkin and Mark Olson, agree. We'll also find out what they expect to hear from current Fed Chief Ben Bernanke at Tuesday's FOMC meeting.
--It could also be a big session for financials with Bank of America losing more than 8 percent last week. Do you buy or bail on this beaten down group?
Don't forget to vote in today's Street Poll, which asks who's got the US credit rating right: Standard & Poor's or Moody's and Fitch? Share your opinion.
Squawk on the Street comes to you live from the New York Stock Exchange each weekday morning at 9 a.m. ET.