T212 transaction data for tax return

[Dougal1984]

@Richard.W

How do I figure my capital gains tax liability?

You add up all the sales which have resulted in gains. You add up all the sales that have resulted in losses. Everything must be figured in GBP. You will need to know the original costs to compute the gains and losses. Make sure to read below “What are the share matching rules?”

Suppose the gains add up to G. Suppose the losses add up to L. You are taxed on G-L-12,300 if this is positive, and have 0 tax if this is negative. The tax rate depends on the tax band in which your most highly taxed other income falls. If this is basic rate (other income <50k) the tax is 10%. If this is higher rate (other income >50k) the rate is 20%.

You do not want to waste the tax free allowance. Suppose you had G=30k, L=20k. You will owe not tax since G-L-12300< 0, but you will have wasted some of the allowance. It would be better to declare losses of just 17700. Now 30000-17700-12300 = 0. You do not declare 2300 of the losses, but prefer to wait to declare them in a subsequent year. Losses can be declared up to 4 years after they actually were realised.

There is some useful details on this thread to help you out.