Greek Finance Minister Giorgos Papaconstantinou called for a ban on derivative trading techniques that increase debt costs for countries in a move that Brussels is considering even though it is not seen as the source of Greece’s problems. Papaconstantinou, who is accompanying Prime Minister George Papandreou on a four-day trip to the US, said that there is a «broader problem with speculation» that has been blamed for making Greece’s fiscal woes deeper. «What has become very clear in this affair is that over and above the fiscal problems that any particular country has… there are some questions about what kinds of use people make of things such as credit derivative swaps, how opaque these markets are, how it’s not clear who’s trading what and how these can push countries… to the brink,» he told CNBC in an interview. Ahead of scheduled meetings at the White House with President Barack Obama and Treasury Secretary Timothy Geithner, Papaconstantinou said more regulation and transparency was needed in markets for insurance-like products called credit default swaps (CDS), including measures such as a ban on «naked short selling.» Naked selling involves selling a CDS to a buyer who does not hold the underlying sovereign bond. European Commission President Jose Manuel Barroso said yesterday the Commission will consider banning these market instruments, pointing out that Greece’s «current» problems weren’t caused by speculation, but rather by overspending. The European Union’s executive would like the G20 group of developed and developing nations to discuss speculation in CDS. «In the short term, we must achieve the necessary coordination to ensure that member states act in a coordinated fashion,» he said. «In this context, the Commission will examine closely the relevance of banning purely speculative naked sales on credit default swaps of sovereign debt,» Barroso added.