(4)IFRS 2 does not specify which valuation models should be used. Instead, it only describes the factors that should be at least taken into account when estimating the fair value of share based payments. This was done on purpose in order not to prevent the development of appropriate measurement techniques which hitherto do not exist for all forms of share based payments (e.g. non tradable long term employee stock options). New alternative methods might be developed in the future to accommodate the needs of companies, auditors and investors. In particular, newly listed companies or companies without a sufficient track record might have difficulties to estimate future share prices.