Gengulphus wrote:GeoffF100 wrote:I update my spreadsheet with the exact values of my trades as I go. For the last trade, I set the amount to be realised to the exact amount of allowance that I have left. iWeb rounds the trade size down, even for sales, so I am under my allowance by at most the price of one share. ...
I don't really see that, because the CGT allowance is a limit on the gains that you realise by your sales, not on the proceeds of those sales, and they're not the same unless you have some shares with zero base cost to sell (which is possible, but it's pretty rare in practice). E.g. if you're selling shares that have doubled in price, the value of the sale that you want is twice the amount of CGT allowance you have left plus the selling commission - but variations in share price will make the exact multiple of the remaining CGT allowance that you want vary as well...
But basically, what you say about being under the allowance by at most the price of one share does answer my actual question, which was essentially "How much accuracy is 'accurate' meant to require?". And yes, I think that in normal circumstances, something pretty close to that accuracy is achievable by the sort of technique you describe. But does the CVR value uncertainty's effect on the base cost apportionment detract appreciably from that level of accuracy?
The number of shares sold and the proceeds of each sale are the only variables that I do not know in advance. The spreadsheet already contains the numbers of shares and the base costs for each holding. When I enter the number of shares sold and the proceeds, it calculates the gain from that sale, and adds it to the gains from previous sales. (It also works out the number of shares remaining and the base cost of those shares.)
Actually, my spreadsheet has three sections:
(1). The first section calculates the amount of each stock I have to sell to fill my allowance, based on prices that are fifteen minutes or so out of date. (I fill my allowance by trimming my largest holdings to a common level.)
(2). The second section is as already described.
(3). The third section uses data from the second section to calculate revised amounts of stock to sell.
As far as the GVC takeover is concerned, the capital gain/loss is insensitive to the value of the CVRs, because the CVR value is only about 7% of the offer, and the difference between the the two GVC share prices is only about 1%.
I believe that most logical calculation uses the closing LCL and GVC prices on the last day of trading to estimate the value of the CVRs, and the opening GVC price on the effective date to apportion the base costs. We will have wait to see what HMRC decides, but it is not going to make much difference, unless you have a huge number of shares.