CG27220 | Partnerships: Calculating a fractional interest in a partnership asset
From HM Revenue & Customs · Capital Gains Manual
CG27150 explains that partners are treated as owning fractional interests in each of the assets of the partnership and that a disposal occurs when a partner's fractional interest in an asset is reduced. This may occur on the disposal of an asset by the partnership or on a change in the partners' sharing ratios.
A partner's fractional interest in a partnership asset should be determined by reference to:
any specific agreement which sets out how capital assets are to be allocated, or if there is no such agreement,
any agreement or other evidence which sets out how capital profits are to be shared, or if there is no such agreement or evidence,
any agreement or other evidence which sets out how income profits are to be shared, or if there is no such agreement or evidence,
Section 24 (1) Partnership Act 1890, which provides that assets should be treated as held by the partners in equal proportions, see BIM82055.