STSM041250 | Exemptions and reliefs: exemptions: treasury shares
From HM Revenue & Customs · Stamp Taxes on Shares Manual
See STSM021260 and STSM075000 for more information on how company purchases of own shares, including for transfer to treasury, are dealt with.
For stamp taxes purposes, where a company has purchased its own shares to be held as treasury shares, no charge to SDRT or Stamp Duty (at either the principal 0.5% or higher 1.5% rate (see STSM053120)) arises on any subsequent transfer of the shares out of treasury.
Similarly, no charge arises where shares held in treasury are cancelled.