Questor share tip: Don't buy Twitter it is too risky Analysis by Forbes found that the average first-day returns of 19 US flotations since September 12 were around 60pc, however, very few people are allocated shares ahead of the listing - mainly staff, early investors and institutions. Those looking to buy the shares on the first day of trading must forget about those sort of gains and focus on Twitter's long-term potential. If the shares rise sharply when trading opens, UK investors will be expected to pay 24 times forecast 2014 revenue of $1bn. Facebook went public at a value of $100bn, or 20 times its 2012 revenue. When you are paying that much for a company that has still not generated cash profits from all that revenue it increases risk. UK investors who are still looking to buy into Twitter can purchase shares as most British stockbrokers deal in American companies, although you must fill in a W-8BEN tax form first. Alternatively, they can bet on the shares" price movements through spread-betters. Twitter's profitability is still under question. Questor needs to see more cash profits from a full year's earnings, preferably several years of audited results, before investing in this flight of fancy. There are also restricted stock units and options which total around $1.6bn issued to staff and investors that could dilute earnings and weigh heavily on the profits in the next four years. The number one rule in investment is the preservation of capital and there is no harm in letting this opportunity pass by.