RSU Tax UK Explained: What You Actually Owe and When

Most people receiving RSUs from a UK employer assume the tax is handled automatically and move on. It often isn't — and a surprise PAYE underpayment or a CGT bill you didn't budget for can wipe out a significant chunk of what looked like a generous equity package. According to HMRC data, restricted stock unit awards are now one of the most common sources of unexpected income tax liabilities for employees in the technology and financial services sectors. Here is exactly how RSU taxation works in the UK, broken down by each stage.

How RSUs are taxed at vesting: the PAYE event

The critical point to understand: RSUs are not taxed when they are granted. They are taxed when they vest — meaning the moment the shares are transferred to you and the restriction is lifted.

At that point, the full market value of the vested shares is treated as employment income. HMRC classes this as a "securities income charge" under Part 7 of the Income Tax (Earnings and Pensions) Act 2003. Your employer is required to operate PAYE on that amount, which means:

• Income tax at 20%, 40%, or 45% (depending on your total income for the tax year)
• National Insurance contributions at 8% on earnings between £12,570 and £50,270, and 2% above that (2025–26 rates)
• Your employer also pays secondary Class 1 NICs at 13.8% on the same amount — though this does not come out of your pocket directly

Example: 500 shares vest on a day when the share price is £40. The taxable amount is £20,000. If you are a higher-rate taxpayer (40% income tax band), you owe approximately £8,000 in income tax plus around £400 in employee NICs. Your employer should withhold this through PAYE, but the mechanism varies.

Many employers use a sell-to-cover approach: they automatically sell enough shares to cover the tax liability and transfer the net shares to you. Others transfer all shares and expect you to pay the tax liability yourself via Self Assessment. If your employer uses the second method and you spend the cash value of those shares, you may find yourself with a significant tax bill in January.

Always confirm with your employer or their equity plan administrator which method they use.

RSU tax UK explained: the difference between vesting and selling

Once shares vest and you receive them, a second potential tax event occurs when you sell those shares. This is where Capital Gains Tax (CGT) applies — but only on any gain made after vesting.

The CGT calculation is straightforward:

• Cost basis = the market value of the shares on the vesting date (the amount already taxed as income)
• Taxable gain = sale price minus cost basis
• CGT rates (2025–26): 18% for basic-rate taxpayers, 24% for higher and additional-rate taxpayers on investment gains (following the October 2024 Budget changes)
• Annual exempt amount: £3,000 per individual (reduced from £12,300 in 2022–23)

If you vest shares at £40 and sell immediately at £40, there is no CGT — you have no gain above the cost basis. If you hold and sell later at £55, the £15 per share gain is subject to CGT.

This is one reason some employees sell immediately at vesting: it eliminates CGT exposure. Others hold shares expecting further appreciation, accepting CGT risk in exchange for potential upside. Neither approach is universally correct; it depends on your confidence in the company's performance and your overall tax position.

If you hold shares across multiple vesting tranches, HMRC uses a share pool (Section 104 pool) to calculate your average cost basis when you sell. This can complicate CGT calculations — it is worth using dedicated software or an accountant if you have multiple tranches over several years.

Self Assessment and RSUs: do you need to file?

If your employer correctly withholds all tax at vesting via PAYE, and you sell the shares immediately with no CGT gain, you may have no Self Assessment obligation. In practice, many RSU recipients do need to file, for one or more of the following reasons:

1. Your employer did not withhold the correct amount — this is common when shares are held rather than sold to cover, or when the employer's payroll processes the vest date incorrectly
2. You have a CGT liability — any CGT gain above the £3,000 annual exempt amount must be reported
3. Your total income exceeds £100,000 — at this level, the personal allowance begins tapering (£1 reduction for every £2 over £100,000), which can push your effective marginal rate to 60% on income in the £100,000–£125,140 band. RSU vests can push you into or further through this band unexpectedly
4. You are a director or have other untaxed income sources

The Self Assessment deadline for online filing is 31 January following the end of the tax year. CGT on UK shares can also be reported via HMRC's real-time CGT reporting service within 60 days of completion if you prefer not to wait until Self Assessment — though for employee shares, annual Self Assessment is typically the relevant route.

RSUs and the £100,000 trap: a common blind spot

The income band between £100,000 and £125,140 deserves special attention. Within this range, the personal allowance (normally £12,570) is withdrawn at a rate of £1 for every £2 earned above £100,000. The result is an effective 60% marginal income tax rate on earnings in that band, plus employee NICs.

If your base salary is, say, £95,000 and a large RSU tranche vests in a single tax year pushing your total income to £130,000, a portion of that vest is taxed at an effective 60% rate — not the 45% additional rate you might assume.

Strategies to mitigate this include making additional pension contributions to reduce your "adjusted net income" below £100,000, or discussing with your employer whether vesting can be structured across tax years (this is rarely possible but worth asking about).

Understanding this dynamic is essential when evaluating whether an RSU-heavy package is genuinely competitive. A nominal £30,000 annual RSU grant at a company where this regularly pushes you into the £100,000–£125,140 band is worth materially less in net terms than it appears. For a fuller breakdown of how to evaluate these components together, see What is total compensation? and the full guide to evaluating a job offer.

If you are comparing an RSU-heavy offer against one with a larger base salary, the RSU vs stock options guide covers how the tax treatment differs between the two instruments — a relevant comparison for anyone weighing offers from US-listed versus early-stage companies.

Benchmarking RSU packages against market data

Tax mechanics only matter in the context of whether the underlying grant is competitive. According to ONS ASHE 2024 data, median total compensation for software engineers in London sits around £72,000–£85,000 depending on seniority, with equity forming an increasingly large share of packages at larger technology employers. At p75 and above, equity components routinely represent 20–40% of total annual compensation.

When evaluating an offer, the relevant question is not just "what is my salary" but "what is my total comp after tax, and how does it compare to market?" A £75,000 base with a £20,000 annual RSU grant at a company with a stable share price is a structurally different offer from £90,000 base and no equity — and the comparison shifts again once you account for the tax treatment described above.

You can benchmark the full package — salary, bonus, equity value, and location — using CompVerdict — total compensation checker, which pulls from ONS ASHE (UK), BLS OEWS (US), Destatis (Germany), and other official government sources to return an instant verdict. If negotiation is the next step, the negotiating total comp guide covers how to frame equity conversations specifically.

For a deeper look at assessing the equity component in isolation, how to evaluate stock options applies much of the same framework to options grants.

Frequently asked questions

When exactly does RSU tax become due in the UK?

Tax is due at the point of vesting — when the shares are unconditionally transferred to you. This is the "employment income" event under UK tax law. Any subsequent gain between the vest price and the sale price is a separate CGT event, reported via Self Assessment for the tax year in which the sale occurs.

What if my employer is based outside the UK but I work in the UK?

You are still liable for UK income tax and NICs on RSUs that vest while you are UK-resident and employed in the UK. If your employer does not operate UK PAYE (as is sometimes the case with foreign employers without a UK payroll), you are responsible for self-reporting and paying the tax directly through Self Assessment. HMRC is aware of this gap and has increased compliance activity in this area.

Can I reduce my RSU tax liability through pension contributions?

Yes. Additional pension contributions (including salary sacrifice if your employer supports it) reduce your "adjusted net income," which is the figure used to assess higher-rate tax thresholds and the personal allowance taper. If RSU vesting is pushing you into the 40% band or the £100,000–£125,140 effective 60% band, pension contributions are one of the few legitimate mechanisms to reduce the liability. The contribution must be made in the same tax year as the vest.

Do I owe tax on RSUs if the shares are worthless by the time I sell?

The income tax charge is based on the value at vesting, not at sale. If shares vest at £40 and fall to £0, you still owe income tax on the £40 vest value. You would have a capital loss on the disposal, which can be offset against other capital gains in the same or future tax years — but you cannot use capital losses to offset the income tax already charged at vesting. This asymmetry is a genuine financial risk of holding unvested or vested equity in volatile or pre-IPO companies.

RSU tax in the UK is manageable once you understand the two-stage structure: income tax at vesting via PAYE, and CGT on any post-vest gain at sale. The main risks are underpayment at source, the personal allowance trap above £100,000, and holding concentrated equity in a single company without accounting for the tax cost already embedded in the position.

If you have received a job offer that includes RSUs and want to know whether the total package — salary, bonus, and equity combined — is competitive for your role, level, and location, run it through CompVerdict. The tool benchmarks against official government salary data across 12+ countries and returns a verdict in under 30 seconds, free, with no sign-up required.