Section 431 Election: What It Is and Why It Matters

TL;DR Summary

• A Section 431 election allows UK employees to pay tax upfront on the full value of restricted shares they receive from their employer.
• It ensures future gains are taxed as capital gains, not ordinary income — reducing potential tax rates from up to 48% to up to 24%.
• Must be signed by both employee and employer within 14 days of share acquisition.
• It’s not filed with HMRC, but must be retained for compliance and reported in the ERS return.

What Is a Section 431 Election?

A Section 431 Election allows UK employees to pay income tax upfront on the unrestricted market value (UMV) of shares they receive, even if those shares are subject to restrictions such as forfeiture or limitations on sale.

By making this election:

• Employees can avoid additional tax charges in the future if the value of the shares increases once those restrictions are lifted.
• ‍Main Benefit: Future share growth is taxed as capital gains (14–24%) instead of being partially taxed as ordinary income (up to 48%), reducing potential tax liabilities for employees and employers alike.

To put this into action, a Section 431 election (also known as an S431 election) is a joint tax election signed by both the employer and employee within 14 days of share acquisition.

Why Does a Section 431 Election Matter?

When employees acquire shares through employment, those shares are often restricted and therefore their immediate value is lower. A Section 431 election allows the employee and employer to agree to treat those shares as if they were acquired at their full unrestricted value from day one, paying any necessary tax upfront and locking in capital gains treatment for future growth.

Without a Section 431 election:

• Part of any future share growth may be taxed as high-rate income.
• The company could face unexpected PAYE and NIC liabilities at exit events.
• After exercising options, employees might have to pay taxes before selling the shares.
  

In short: Failing to make a Section 431 election can cost both employees and companies significantly more in taxes later.

How to Make a Section 431 Election

To execute a valid Section 431 election, both the employee and employer need to follow a few key steps. The most important being that the election be signed jointly within 14 days of the acquisition of shares, as there are no extensions and no exceptions.

While the election isn’t filed with HMRC, it must be securely retained by the company. Electronic signatures are allowed, and storing the signed election alongside your broader share plan documentation ensures you’re prepared for audits, due diligence, or any HMRC inquiries.

Slice Global Tip: Automate election signing at the same time as share issuance paperwork to prevent missed deadlines. Making a Section 431 election isn’t necessarily complicated but it does require precision and timing. The good news? When you have the right processes in place, you can execute it quickly and confidently.

Below is a step-by-step guide to ensure nothing slips through the cracks:

1. Prepare a Valid Template. Use an HMRC-compliant Section 431 election form.
2. ‍Joint Signatures. Ensure both employee and company sign the election.
3. ‍Record the Date. Sign within the strict 14-day limit after share acquisition.
4. ‍Store the Election. Keep the signed document securely for at least the life of the shares.
5. ‍Annual Reporting. Reflect the election appropriately in your ERS annual filing to HMRC.
   

Common Mistakes with Section 431 Elections (and How to Avoid Them)

Most issues with Section 431 elections come down to timing, communication, or documentation, meaning they’re almost always preventable. The most common pitfall? Missing the 14-day deadline, which is why it’s recommended that the election be signed at the same time shares are issued. Another common challenge is employee hesitation; many simply don’t understand the tax benefits of signing, so a quick, clear explanation can go a long way.

Remember, we may understand why the S431 election is an incredible opportunity, but if it’s not communicated early to your employees, you may have to explain why it wasn’t later. Lastly, In fast-moving start-up environments, it’s easy for paperwork to slip through the cracks especially when processes aren’t centralized. That’s why storing signed elections in a secure, backed-up system should be heavily considered.

Section 431 vs Section 83(b) Election

If you’re familiar with equity compensation in the US, you might recognize some parallels between the UK’s Section 431 election and the U.S. Section 83(b) election. Both serve a similar purpose: locking in capital gains treatment by taxing the value of shares upfront. But the finer details like deadlines, filing methods, and who needs to sign are different enough to trip people up, especially in cross-border plans with global participation. Here’s how the two elections compare side by side.

Summary: Both elections aim to protect future growth from being taxed as income, but the UK requires faster and mutual action.

When Should You Make a Section 431 Election?

To help you better educate employees on when a Section 431 election makes sense, we’ve included a quick-reference table below. It outlines common scenarios, the recommended action in each case, and why it matters. Feel free to share this resource directly with your employees!

Pro Tip from the Slice Global team: It’s safer to sign a Section 431 election even if you think it's unnecessary than to miss one when it's required.