FSA has published a Dear CEO letter to CEOs and others responsible for valuation and controls in large or complex principal trading operations in investment firms and banks. It warns them of its intention to visit firms in early 2009 to assess their compliance with FSA’s prudent valuation principles. It explains the principles and what FSA expects firms to have done about them. The letter also sets out the background to some recent mis-markings and what the firms could have done to avoid them.