CG12312 | Options: grant of an option
From HM Revenue & Customs · Capital Gains Manual
TCGA92/S144 (1)
The grant of an option over a chargeable asset owned by the grantor may create an interest over that asset. This would normally be treated as a part disposal of that asset in accordance with TCGA92/S21 (2)(b), but TCGA92/S144 (1) specifically provides that the grant of an option is to be treated as the disposal of an asset, namely the option itself, and not a part-disposal of the asset over which the option is created, see Openshaw v Strange and Others 57TC544.
TCGA92/S144 (1) applies also to the grant of options over assets the grantor does not own.
To summarise:
the grant of an option is a disposal of an asset, the option, by the grantor, and
in computing the gain or loss accruing to the grantor on the disposal the only allowable expenditure is the cost of granting the option.