The UK operates a participation exemption called the "substantial shareholding exemption". Assuming all the relevant entities or groups are trading companies and groups, if a company together with its fellow group companies has a shareholding of over 10% in another company, and has held those shares for more than twelve months, disposals of those shares are exempt from chargeable gains. The figure of 10% is increased to 30% for shares held by the long-term insurance fund of a life assurance company. The detailed rules, however, are complex, and companies need to study them closely to see whether the substantial shareholding exemption applies.