European Central Bank President Jean-Claude Trichet said a lack of transparency is one of the main causes of the financial market turmoil of the past nine months. "The present turbulences have, once more, demonstrated that opacity regarding the stance of markets, financial instruments or financial institutions is a recipe for catastrophe," he said in a speech. "In the prelude to an episode of uncertainty and turbulence, absence of transparency inevitably triggers contagion and negative herd behaviour - we saw this at the heart of the Asian crisis, we very much also see it at the heart of the present episode," he said. Trichet said the absence of pertinent, credible and reliable information drives market participants to assume the worst possible hypothesis on the position of financial institutions and instruments and to act accordingly. He said it is essential to increase transparency as an insurance policy against irrational herd behaviour and unjustified contagion in times of stress.