The Financial Times today published a letter from Standard & Poor's executive managing director Vickie Tillman saying that Arturo Cifuentes is incorrect to claim (See Say no to black boxes, comments Cifuentes) that S&P's CDO model, CDO Evaluator, is a black box. Tillman writes that CDO Evaluator can be dowloaded for nothing from S&P's website and comes with a user manual which discloses assumptions on default probability, recovery and correlation, as well as showing the formulas that drive the model. She says S&P has long been committed to transparency.