S129 and share identification

[benjam1n]

Assume a shareholder acquires 100 ordinary unquoted shares in 2000 for £100.

In 2007, he exchanges them for 100 A shares worth £3 each and 100 B shares worth £1 each

In 2009, he acquires 50 A shares for £4 each (£200)

In 2010, he disposes 25 A shares for £5 each. The 100 B shares are still worth £1 each.

S129 TCGA 1992 stipulates the base cost of the ordinary shares is split between the A and B shares on a subsequent disposal, not at the time of the reorganisation.

This would be fine but for the acquisition in 2009, as I now have a pool of 150 A shares, but I do not know what the cost is of 100 of them.

The formula at CG51892 is

Base cost x MV of part disposed/(MV of part disposed + MV of part retained)

The MV of part retained will include the B shares as per S129.

But I do not know what my base cost is - if I make it £300 (being the initial £100 plus the 2009 acquisition of £200), then the B shares base cost will benefit from the 2009 acquisition of the A shares.

Do I keep the 100 A shares and 50 A shares in separate pools? If so, do I match the disposal in 2010 on a LIFO basis? I.e. against the 2009 acquisition.

Any thoughts would be appreciated,

Thanks in advance

Ben

[benjam1n]

Does anyone have any thoughts on this?