Thank you. The position then is that you will take the property at the market value it was valued at at the time of your grandmothers passing. It would have been valued for probate purposes at that time and if you do not have a record of the valuation, you can either contact the person or solicitors that handled the administration for a copy of the estate return to confirm the valuation. If this can not be located, then a new historical valuation will need to be obtained from a local estate agent that has a qualified surveyor working for it - most larger agents do. Your gain is the difference between the market value when you inherited and the value when you eventually come to sell.
Your sister will not pay CGT but if the gain is more than your annual allowance which is £11,300 then you will pay CGT on any gain over this sum. Note that if you have any losses from previous years, you can carry these forward and use them to offset any tax.
In terms of your proposal, you can gift or sell your sister your share however if you gift it , it is still treated as being transferred at market value and tax will be due in the same way so this will not assist. What you can do however is git or sell your sister shares in the property each tax year so as not to exceed your allowance. So for example let us say that the property is worth £200,000 and was £100,000 when you acquired it. The gain is £100K ad your share is £50K. If you transferred your whole share now, you would pay tax on £38,700 gain (being the gain less your allowance.
However is you transferred your share to your sister in £22,600 tranches each tax year then the amount transferred would be within your annual allowance and no tax would be due. Depending upon the amount of gain you may be able to do this over anywhere between 1 and 3 years most likely epending on how much the property has increased in value. Youmay wish to retain an accountant to work out the amount you can transfer once you have the above valuations if you are not certain of the figures.
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