The reason for the rise is the increase in the geo-political risk premium because of the situation in Iran.

Investors are now going to build a higher risk premium into their bottom line.

Concern about supply means the risk premium in prices is on the rise. Iran is the major problem, but Nigeria coming on top makes matters worse.

The IAEA meeting is paramount on investors' minds, because it has the potential to alter the demand supply equilibrium.

Asian central banks have been huge buyers of Treasuries, so if they're going to be buying less to hold down their currencies, then Treasuries will fall.

Prices haven?t fallen by much because of the heavy refinery maintenance seen around March, which still raises some concerns over supply particularly for gasoline.