So C just borrowed $7.5 billion at the 11% rate, and those are convertible bonds, meaning the lender may get even more (as I recall when Countrywide placed a convertible bond few months ago they got a 2% interest on that).
What is the main C business? I guess lending money. The best business customers are getting prime rate, which is 7.5%. Mortgage interests are between 6.5% and 9%, unless you offer a mortgage to a homeless unemployed, which probably will pay much more than that.
So now C is officially losing few % on every $ they lend.
As people say they are the largest subprime borrower on the planet now. Next step will be selling assets and cutting dividends
Update: Mish made much more accurate analysis