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HMRC internal manual

Inheritance Tax Manual

Transfers on death: unquoted shares - undue hardship

Unquoted shares or securities that do not represent a control holding (IHTM30217) of a company qualify for instalments if the Board are satisfied that the tax attributable to their value cannot be paid in one sum without undue hardship.

You should refer any claim for instalments under IHTA84/S228 (1)(c) immediately to your manager. Further instructions on the operation of IHTA84/S228 (1)(c) are given in connection with potentially exempt transfers (PETs) (IHTM30254).