From the Wall Street Journal this morning- this is worth watching:

A sharp and unexpected rise in a widely used interest rate is threatening to add billions of dollars to the interest bills of homeowners, companies and other borrowers around the world.

The London interbank offered rate jumped for the second straight day Friday — two days after the British Bankers’ Association, which oversees the calculation of the interest rate, said it was investigating the borrowing rates that banks had been providing to it.

The BBA started its review amid growing concerns among bankers that their rivals weren’t reporting their true high borrowing costs, for fear of signaling to the market they were desperate for cash. John Ewan, a manager of the Libor system at the BBA, said Friday the association continues to believe in the accuracy of the Libor system.

What’s the big deal if the LIBOR’s rise is sustained?

The past week’s rise of Libor could add roughly $18 billion in annual interest costs on that corporate debt, or about $100 to the monthly payment on a $500,000 adjustable-rate mortgage loan.

And there’’s the effect on commercial real estate to consider as well:

In commercial real estate, the rise in Libor is bound to have a chilling effect, because many developers borrow heavily using floating-rate debt linked to Libor. Until recently, declining rates had benefited borrowers, but some lenders were growing wary. Banks have started to include a floor in Libor-linked loans, said Peter Fitzgerald, chief financial officer at Radco Cos., an Atlanta developer. That means borrowers’ savings would be limited if Libor continued to sink, but borrowers can be hit by the latest rise.

"If Libor were at 4% instead of under 3%, there would be a disaster that would take years to unwind," he said.