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HMRC internal manual

Inheritance Tax Manual

Related property: what happens when both the general and special rules apply?

If there are three or more items that are combined for valuing property (IHTM09732) under the related property rules you may get a situation where both the general (IHTM09735) and special (IHTM09736) rules apply. When this happens you should first use the general rule to apportion the aggregate value between the various categories of assets. You should then do a further apportionment using the special rule of the amounts apportioned to each category.