Focus on the longer term implications17 Apr 2022 20:08
The value of your investment will hardly change at all (mathematically) due to the consolidation, even your capital gain is likely to be piffling (see below) and covered by the £12,300 exemption. A better reason to hold or sell is whether you think all this is good or bad for the SP in the longer term. I believe it's good and that's why I'm holding. In fact, I'm even considering buying more before the 13th May.
For those interested here's the maths. It's more detailed than the approximation on the AVIVA site. Let
c = Your typical dealing cost (for example £12.95 with Hargreaves Lansdown);
n = Number of shares you own;
p = Share price at close on Friday 13th May;
q = Share price at close on Monday 16th May (first day of trading after consolidation);
u = Your current unit cost (average cost per share).
The value of your investment before consolidation is np, equation (B), and after consolidation it will be
0.76nq + (1.0169n – c)/1.005, equation (A),
where the division by 1.005 is to take account of stamp duty (0.5%) to get our investment back to its previous invested status (note that from a mathematical point of view it doesn't really matter whether you reinvest your returned capital in Aviva or other shares, we are simply ensuring we're comparing like for like).
Equating (A) and (B), setting them equal to one another, we get
np = 0.76nq + (1.0169n – c)/1.005,
and so for this to be a no gain, no loss transaction we require
q = (np – (1.0169n – c)/1.005)/0.76n.
For example, assuming the closing price on Friday 13th May is equal to today's sell price of p=4.341, with a holding of n=2,000 shares and dealing cost of c=£12.95, then q=4.3889. So if the closing price is exactly this on Monday 16th May the transaction will have had no effect mathematically on the value of the investor's holding. Note that this requires the SP to close about 1.1% up from the close on Friday 13th May.
Your capital gain from the returned capital due to the redemption of the B shares is
1.0169n(1 – u/(1.0169 + 0.76q)).
That's £104.62 using the example figures.