(1) For the purposes of this section 'old assets' and 'new assets' have the same meanings as in section 597.
(2) Subject to subsection (4), for the purposes of section 597 all the trades to which this section applies carried on by members of a group of companies shall be treated as a single trade (except in a case of one member of the group acquiring, or acquiring the interest in, the new assets from another member or disposing of, or disposing of the interest in, the old assets to another member).
(3) This section applies to -
(a) any trade carried on by a company which is resident in the State, and
(b) any trade carried on in the State through a branch or agency of a company which is not so resident.
(4) This section shall not apply unless -
(a) the company disposing of the old assets is resident in the State at the time of the disposal, or the assets are chargeable assets in relation to that company immediately before that time, and
(b) the company acquiring the new assets is reside
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