With poetic timing, the FTSE finally did it. Almost a year to the day of the anniversary of the Lehman Brothers collapse, the London blue-chip index closed above the 5,000 point barrier on Friday after a tour de force week in which the market stormed up 160 points. The week ahead however is likely to start off on a more cautious note as traders prepare to be inundated with economic news which could potentially upset the party mood for what can be expected to be a particularly volatile few days. News out from the US includes retail sales and the producer price index tomorrow, the consumer price index and industrial production data on Wednesday and housing starts on Thursday. UK retail sales are released on Thursday, with an annual increase slowing to 2.8 per cent the forecast. <br /><br />On top of all the data this is “quadruple witching” week, when traders adjust positions to be ready for the quarterly expiry of positions on index and equity futures and options.<br /><br />Markets have a habit of moving in rather erratic ways during this time when we have a hot cauldron of options exercising, delivery of underlying markets, hedging, as well as the inevitable arbitrage and speculation. <br /><br />GFT is calling the FTSE 100 to start the week on a warily negative note, dipping back below 5,000, with an opening level expected of 4,992, down 19 points from Friday’s close. The German DAX is called down 11 points at 5,613 and the French CAC is quoted to open down 10 points at 3,724<br />Martin Slaney is head of derivitives at GFT Global Markets.