RE: Share Price8 Dec 2025 14:50
To apportion costs for Capital Gains Tax (CGT) in a demerger, you divide the total allowable cost of your original shares between the new shares in the demerged entity and any shares retained, using a formula based on their comparative values. The formula is:
(Cost of Original Shares) x (Value of Shares Disposed Of) / (Value of Shares Disposed Of + Value of Shares Still Held).
So say you previously owned 100 ULVR shares which cost you a total of £3,800 then your base cost for your MICC shares (of which you will have 20) would be calculated as follows (given an opening SP today of 1100p for MICC and an opening share price today of 4342p for ULVR):
Value of Shares Disposed Of = £11.00 x 20 = £220.
Value of Shares Still Held = £43.42 x 100 = £4,342
So for CGT purposes your allowable cost for your MICC shares is:
£3,800 x 220/(220+4342) = £183.25
Thus, the quick way to find your allowable costs for you new MICC shares is just multiply your allowable costs for your original ULVR shares by a factor of 0.048224463 and reduce the allowable costs of your ULVR accordingly.
That's how the calculation should go baring arguments over opening share prices. Hargreaves Lansdown says the opening SP of MICC is 1100p but this site says it's 1220p! So that could change the calculation slightly. Note that this site and HL are in agreement over the opening SP of ULVR, 4342p. If we are using the 1220p MICC opening SP then the multiplying factor is 0.053205408.