A select group of Venezuelan banks is profiting from opaque government treasury operations involving hundreds of millions of dollars of Latin American sovereign bonds under a financial programme fostered by President Hugo Chávez.

Backed by record oil revenues, Venezuela has bought $1.6bn in Argentine debt during the past year - mostly dollar-denominated Boden bonds maturing in 2012. They were purchased in auctions that were eschewed, in some cases, by big investment banks, such as Citigroup and JPMorgan Chase, because the yields offered were considered too low.