In section 421 a "participating interest" means an interest held by an undertaking in the shares of another undertaking which it holds on a long-term basis for the purpose of securing a contribution to its activities by the exercise of control or influence arising from or related to that interest.
A holding of 20% or more of the shares of an undertaking is presumed to be a participating interest unless the contrary is shown.
The reference in subsection (1) to an interest in shares includes—
and an interest or option falls within paragraph (a) or (b) notwithstanding that the shares to which it relates are, until the conversion or the exercise of the option, unissued.
For the purposes of this section an interest held on behalf of an undertaking shall be treated as held by it.
In this section "undertaking" has the same meaning as in the Companies Acts (see section 1161(1) of the Companies Act 2006).