CTM03590 | Corporation Tax: small profits relief: whether trade or business carried on - decided cases
From HM Revenue & Customs · Company Taxation Manual
When considering whether companies are associated, whether a company is carrying on any trade or business is determined on an accounting period by accounting period basis. Where a company would be associated for part of an accounting period only, consideration is restricted to activity in that part.
Meaning of business for CTA10/S25 (3)
Most companies will either be trading or have a readily identifiable business. In the main, excluded companies will be:
wholly dormant companies
On the question of contrasting trading and business the following principles from decided cases may be helpful.