What Is a Share Incentive Plan? A Complete UK Guide

Everything you need to know about UK Share Incentive Plans: the four share types, who can join, how the trust works, and the tax treatment — in plain English.

1. What Is a Share Incentive Plan?

A Share Incentive Plan, usually shortened to SIP, is a type of UK employee share scheme that lets you own shares in the company you work for, on tax-advantaged terms set by HMRC. It's one of four tax-advantaged share schemes recognised in UK legislation, sitting alongside Save As You Earn (SAYE), Enterprise Management Incentives (EMI), and the Company Share Option Plan (CSOP). Unlike the other three, which are built around options — the right to buy shares later at a fixed price — a SIP is built around actually holding real shares from day one, sitting inside a trust set up by your employer.

The legal basis for SIPs sits in Schedule 2 to the Income Tax (Earnings and Pensions) Act 2003 (ITEPA 2003) — SIPs are sometimes called "Schedule 2 SIPs" in HMRC's own guidance. That legislation, plus HMRC's Employee Tax Advantaged Share Scheme User Manual (ETASSUM), is the authoritative source for everything on this page.

In practice, a SIP does three things at once: it gives you a stake in your employer's success, it can save you Income Tax and National Insurance compared with taking the equivalent value as cash salary, and — if you hold the shares for long enough — it can let you take that value out completely free of Income Tax and National Insurance.

Run your own numbers with our Share Incentive Plan Calculator as you read through the rules below.

2. Why Do Employers Offer SIPs?

SIPs exist because the UK government wants to encourage wider employee share ownership. That policy goal is also why SIPs come with a key legal constraint that shapes almost everything else about them: a SIP must generally be offered to all employees on similar terms — a company can't set one up just for directors or its highest earners. Reasonable eligibility conditions are allowed (such as a minimum length of service, up to 18 months), but the scheme as a whole has to be genuinely all-employee.

For employers, SIPs are a relatively low-cost way to offer a meaningful benefit: they get favourable tax treatment, and unlike a straight pay rise, part of the cost is effectively funded by the employee's own contribution through partnership shares.

3. The Four Types of SIP Shares

A single SIP can combine up to four distinct kinds of share award, each with its own rules. A company doesn't have to offer all four — check with your employer which your specific plan includes.

Free Shares. Your employer can give you free shares at no cost to you, up to £3,600 in a tax year. These can be awarded equally to everyone, or linked to objective performance measures applied consistently.

Partnership Shares. Shares you buy yourself, using money deducted from your gross salary — before Income Tax and NIC. The cap is £1,800 a year, or 10% of your salary, whichever is lower. Because the deduction happens before tax, this is where most of the day-one tax saving comes from.

Matching Shares. If your employer offers partnership shares, they can "match" them with further free shares, at a ratio they choose, up to a maximum of 2 matching shares for every 1 partnership share. Matching shares are often subject to a forfeiture condition (commonly up to 3 years).

Dividend Shares. If plan shares pay dividends, your employer can let you reinvest them into further shares rather than taking cash. Since April 2013 there's no statutory cap on reinvestment, though employers can set their own limit.

A fully generous scheme's combined maximum across free, partnership and matching shares in one tax year is around £9,000 (£3,600 + £1,800 + £3,600 at 2:1 matching) — though few employers offer the maximum on every element.

4. Who Can Join a SIP?

As above, SIPs must generally be offered on similar terms to all employees, including part-time staff, subject to reasonable and consistently applied eligibility conditions. Whether you're automatically enrolled or need to opt in — particularly for partnership shares, since that involves a deduction from your own pay — depends on how your employer has set the scheme up. Check your company's SIP invitation or HR/benefits portal.

5. How a SIP Trust Actually Works

Every SIP operates through a trust, set up and administered independently of the company, often via a third-party plan administrator. Shares awarded to you are bought or issued into this trust and held in your name inside it. You're the beneficial owner throughout; the trust exists to administer the scheme and enforce the holding-period rules, not to give the company control over your shares. While shares sit in the trust, you're normally entitled to dividends and can typically direct any attached voting rights, depending on the specific plan rules.

6. What Happens to Your Shares Over Time

Three points matter: while shares are in the trust and you remain employed, no Income Tax or NIC is due simply for holding them. If you leave your employer or withdraw shares before 5 years, the outcome depends on exactly how long they were held (see our holding period rules guide and the Holding Period Calculator). If shares are held 5 years or more, withdrawing them is generally free of Income Tax and NIC entirely.

7. SIP Tax Treatment, in Brief

Full mechanics and worked examples are in our companion guide, SIP Tax Benefits Explained. In short: partnership shares are bought from gross salary, so no Income Tax or employee NIC is due at purchase. Free and matching shares cost nothing, so there's no "saving" in the same sense — but their value arrives tax-free at award, and can become entirely tax-free on withdrawal if held long enough.

8. A Worked Example

An employee earning £35,000 whose employer offers all four SIP elements with a 1:1 matching ratio contributes £100/month (£1,200/year) in partnership shares — under both the £1,800 cap and the 10%-of-salary cap (£3,500), so the full amount goes through. Their employer matches 1:1, adding another £1,200/year, and separately awards £600 of free shares that year.

Total value added to the trust: £1,200 (partnership) + £1,200 (matching) + £600 (free) = £3,000, of which £1,800 came from the employee's own gross salary and £1,200 from the employer at no direct cost. Because the £1,200 partnership contribution came from gross pay, the employee also avoided Income Tax and NIC on it — see the exact figures in the SIP Tax Savings Calculator.

9. SIP vs Owning Shares Directly

You might wonder why not simply buy shares in your employer on the open market. The difference is the tax wrapper: direct purchase gives no Income Tax/NIC relief and no special exemption on gains, whereas a SIP gives both, provided you hold the shares inside the trust for the qualifying period. The trade-off is liquidity and concentration risk — money inside a SIP trust is less flexible than freely-tradeable shares, and (like any single-company holding) concentrates risk in one employer's stock rather than a diversified portfolio.

Frequently Asked Questions

Sources

• HMRC, Employee Tax Advantaged Share Scheme User Manual (ETASSUM) — Share Incentive Plans
• Income Tax (Earnings and Pensions) Act 2003, Schedule 2
• GOV.UK guidance on tax and employee share schemes
• HMRC Capital Gains Manual, CG56490 — Share Incentive Plan (SIP): introduction