SolvedCH82340 | Penalties for Inaccuracies: Calculating the penalty: Losses impact on potential lost revenue calculation: Understatement of aggregate group profits
From HM Revenue & Customs · Compliance Handbook
You must check the date from which these rules apply for the tax or duty you are dealing with. See CH81011 for full details.
Penalties apply to group companies in the same way as to singleton companies.
Where the effect of a careless or deliberate inaccuracy is to understate aggregate group profits or gains, the PLR is calculated in the normal way, see CH82282.
An aggregate profit arises where, for all the companies within the group for Group Relief purposes,
the profits chargeable to CT from which Group Relief could be deducted if it were surrendered, exceed
the amounts available for surrender as Group Relief.