GIM7380 | Equalisation reserves: recalculation of reserves for tax purposes
From HM Revenue & Customs · General Insurance Manual
Companies may be required to recalculate their equalisation reserve for tax purposes in a number of circumstances, namely where
the regulatory returns are drawn up wholly or partially using a non-annual basis of accounting, but tax returns are based on annual accident year accounts (GIM7140)
credit insurance business equalisation reserves have been accumulated prior to accounting periods ending on or after 31 December 1996 (GIM7260)
the insurer operates partly on a mutual, and partly on a non-mutual basis (GIM7360)
the reserve has been challenged on anti-avoidance lines (GIM7350).
Regulation 3 of the tax Regulations provides that a separate reserve will be maintained until such time as the regulatory reserve naturally coincides with it.
There is an example of a shadow reserve calculation at GIM7240.