Proving once again that there is no such thing as a sure-fire winner in the new issue stakes, and that once you set the date for your float it is in the lap of the gods, Cambridge Instruments Plc’s offer for sale was four times oversubscribed, but when trading started yesterday, after opening confidently at 135 pence, it came under the market’s general sour mood, and ended the day at 129 pence for a one penny discount on the flotation price.