Capital allowances: ring fence expenditure supplement: the reference amount for a post-commencement period
CTA2010\S329
The reference amount for a post-commencement period is the amount of the ring fence pool remaining after any reductions required for utilised ring fence losses CTA2010\S327 (see OT26180) and unrelieved group ring fence profits CTA2010\S328 (see OT26185)
GOV.UK