King Digital, the company behind the Candy Crush smartphone game phenomenon, is expected to make its market debut this week. It's one of a host of companies preparing for an IPO, many of them in the tech sector. Saxo Bank's Head of Equity Strategy, Peter Garnry, says there are many opportunities for canny investors but plenty of pitfalls too.

Peter says you have to be careful. King Digital has come from nothing to almost two billion dollars of revenue generation in just a few years; its penetration rate is phenomenal. He's optimisitc of King's future success. The problem, he says, is that the barrier to entry is low, there's huge competition and it's very difficult to maintain the engagement of users over a period of time.

Looking at the valuation key, advises Peter. He also points out that IPOs are protected by investment banks on the long side and they can be difficult to short in the first couple of weeks. however, if you're very active to get in on the open, on a lot of these listings you can make a positive return in a few trading days.