Be careful not to confuse the artificial price set to allow a pseudo trade in the employee share holding with the actual value of NATS or its shares.
Some of the airlines which form the Airline Group are not public companies so it's quite hard to see what value they put on their Airline Group shareholding and some don't put a figure in their Annual Reports. Those that do seemed to assume a value last year of about £10.5 million on an original investment of £6.6 million. Not bad but well down on the 300%. As FTSE shares have fallen about 30% since those reports it would be reasonable to assume some adjustment in NATS share valuation based on likely future income and dividend will be reflected in their 2008/2009 reports when they are published. Their shareholding value is probably just a little bit more than they paid for it but as there's no real market nobody knows for sure.