RE: Billingham15 Dec 2020 22:22
Any gains inside an ISA, SIPP or spreadbet are tax free.
Any gains or losses outside of these in all assets need to netted off in a tax year. Any net gain over £12,300 will be subject to CGT. A gain or loss is only realised when you sell. Any costs involved in buying and selling the asset can be subtracted from the gain.