Fair value measurement after initial recognition of investment in equity instruments

Per FRS 109, para 5.1.1, financial assets such as equity instruments shall be initially measured at fair value. And subsequently measured at amortized cost or fair value per para. 5.2.1

Per para. B5.2.3: In limited circumstances, cost may be an appropriate estimate of fair value. That may be the case if insufficient more recent information is available to measure fair value, or if there is a wide range of possible fair value measurements and cost represents the best estimate of fair value within that range.

Also refer to para. FRS109, B5.2.5 on when must measure fair value.