IHTM34187 | Changes in shareholdings: rights issue
From HM Revenue & Customs · Inheritance Tax Manual
If a rights issue is declared in respect of a qualifying investment () the appropriate person () may
sell the rights ()
take up and sell the allotted shares ()
neither take up nor sell the rights ()
dispose of the rights without consideration (), or
sell part of the rights and accept the balance () of the shares.
The impact on the calculation of the loss will depend on what option the appropriate person takes.