Stamp duty on shares is finally going digital — on 13 July 2026 HMRC published draft legislation for a new Securities Transfer Tax (STT), a single, self-assessed, fully digital tax that will replace both stamp duty and stamp duty reserve tax (SDRT) on transfers of securities, targeted for introduction in 2027. As chartered certified accountants in Surrey advising companies and shareholders across the UK, TaxDigit explains what the new regime means for share sales, company purchases and group reorganisations, and what to do before the rules change.
What Is the Securities Transfer Tax — and Why It Matters
Today, tax on share transfers is split between two regimes: stamp duty, a document-based charge dating back to 1891 that still requires stock transfer forms to be sent to HMRC for stamping, and SDRT, which applies to paperless transactions settled electronically through CREST. Running two parallel systems for what is economically the same transaction creates duplication, delay and confusion — a company registrar cannot lawfully write up the register of members until a stamped instrument comes back from HMRC, which can hold up completions for weeks.
The Securities Transfer Tax sweeps both regimes away. Under HMRC’s policy paper Modernisation of the Stamp Taxes on Shares framework — Securities Transfer Tax, published with draft legislation on 13 July 2026, a single self-assessed tax will apply to transfers of securities, reported and paid through a new online portal. There will be no more physical stamping and no more paper-based reporting or payment.
What Changes From 2027
The government is aiming to introduce the STT and its legislative framework in 2027, with an update on the exact commencement date due in autumn 2026. The key features of the new regime are:
- One tax, one portal — a single self-assessed charge replaces stamp duty and SDRT, reported and paid digitally; CREST will continue to handle transactions settled electronically.
- The purchaser is liable — but an agent (such as your accountant or solicitor) can act as the “accountable person” and deal with reporting and payment.
- Faster completions — a unique taxpayer reference number (UTRN) is generated immediately on submission of the return, and the registrar can write up the register of members as soon as the UTRN is received, rather than waiting for HMRC to stamp a document.
- Clear payment deadlines — 30 days for off-market transfers, 14 days for transactions in electronic settlement systems, running from the earlier of substantial performance or completion.
- Reliefs retained and self-assessed — stamp duty group relief, reconstruction and acquisition reliefs, the growth-market exemption and intermediary relief all carry over, claimed through the portal without waiting for HMRC adjudication.
The Transitional Rule
The draft legislation provides a four-year transitional period for transactions entered into before the commencement date of the new rules. In practice this means agreements signed under the old regime — conditional share purchase agreements, options and deferred completions among them — will need to be tracked carefully across the boundary, because the tax treatment of a deal signed in 2026 but completed after commencement will depend on the transitional provisions. Anyone negotiating a share sale or reorganisation now should consider how the change of regime affects timing.
Who Benefits — and Who Should Still Pay Attention
Buyers of private companies gain the most: no more sending stock transfer forms for stamping, no more weeks-long delays before the share register can be updated, and a clear digital process with an immediate UTRN. Groups undertaking reorganisations keep group relief and reconstruction relief, but these become self-assessed — the burden of getting the analysis right shifts squarely onto the taxpayer and their adviser, with a full compliance regime behind it. Trustees, partnerships and investors holding unlisted shares should also note that transfers of partnership interests are expected to move out of scope entirely under the new framework.
What Companies and Shareholders Should Do Now
- Review any share purchase agreements, options or conditional deals that may straddle the 2027 commencement date and map them against the four-year transitional rules.
- Factor the new 30-day and 14-day payment windows into completion timetables and funds-flow planning.
- Check whether group reorganisations planned for 2027 onwards would be better accelerated or deferred once the commencement date is confirmed in autumn 2026.
- Decide who will act as the accountable person for future transfers — the portal allows your accountant to take on the reporting and payment obligation.
- Respond to the technical consultation, which closes on 7 September 2026, if the draft rules create issues for your transactions.
Frequently Asked Questions
What is the Securities Transfer Tax?
The Securities Transfer Tax (STT) is a proposed single, self-assessed, fully digital UK tax on transfers of securities. It will replace both stamp duty and stamp duty reserve tax, with reporting and payment handled through a new HMRC online portal.
When does the STT start?
The government is targeting introduction in 2027, with an update on the commencement date expected in autumn 2026. Draft legislation was published on 13 July 2026 and is open for technical consultation until 7 September 2026.
Will stamp duty group relief still exist?
Yes. Group relief, reconstruction and acquisition reliefs, the growth-market exemption and intermediary relief are all retained under the new regime, but they will be self-assessed through the portal rather than adjudicated by HMRC in advance.
Do I still need to send documents to HMRC for stamping?
Under the current rules, yes — stock transfer forms for off-market share purchases must still be submitted to HMRC with stamp duty paid within 30 days. Once the STT commences, physical stamping disappears entirely and everything is done digitally.
How TaxDigit Can Help
TaxDigit advises on the tax consequences of company share sales and purchases, group reorganisations and shareholder exits, alongside tax advisory and planning and year-end accounts support. We can review deals that straddle the 2027 changeover, act as your accountable person under the new regime, and structure transactions to preserve group and reconstruction reliefs. The full policy paper and draft legislation are on gov.uk.
Plan Ahead With TaxDigit
If you are buying or selling a company, restructuring a group or holding a deal that may complete after 2027, speak to us before the rules change. Call 01483 230 777, email info@taxdigit.co.uk or book a consultation with our team in Guildford, Surrey.