Capital Gain or Loss in Forex Transaction

Dear HMRC team, Could you please tell me how I should calculate capital gain or loss on the following transaction. On day one, I sell 100 GBP to get 150,000 Japanese Yen, assuming the FX rate was 150. One month later the fx rate became 160 and I needed to sell 160,000 Japanese Yen to get back the original 100 GBP. How do I calculate my capital loss, as I needed to pay 10,000 more JPY? Or since GBP equivalent in each transaction is 100 GBP, is there no gain and loss? Best regards, 

In my above example, i meant to type selling 100 gbp to get 15,000 yen, and then having to pay 16,000 yen later to close the 100 gbp short position due to fx move since, ie loosing 1,000 yen. Which fx rate should be use to determine the GBP equivalent of the loss? Best regards, Emre

Hi,
We cannot comment on any form of calculation/example or scenario, whether fact or fiction.
We can only point you the direction of the guidance, so that you can review the guidance and to allow you to make an informed decision.
Guidance is at Capital Gains Tax: what you pay it on, rates and allowances
Thank you.