The Surprisingly Personal Side of Filing a Partnership Tax Return 

When two or more people go into business together, they often focus on the exciting parts — growth, strategy, splitting profits. But there’s one area that tends to get far less attention until it becomes urgent: tax. Specifically, who’s actually responsible when it’s time to file a partnership tax return? 

The answer isn’t always as simple as “the accountant will sort it.” In fact, it’s surprisingly personal — and understanding where responsibility lies could save your partnership a great deal of stress (and penalties). 

Let’s unpack this often-overlooked side of partnership tax, and why assuming “someone else is doing it” might be the costliest assumption of all. 

One Return But Multiple Responsibilities 

In the UK, all partnerships must submit a Self Assessment partnership return (SA800) to HMRC each year. This includes details of the partnership’s income and expenses and how profits are split between the partners. 

But here’s the twist: even though there’s only one partnership tax return, each partner is individually responsible for ensuring it gets filed. It’s submitted under the name of the “nominated partner,” but HMRC doesn’t see this person as a sole point of accountability. 

If the deadline is missed, or the figures are wrong, every partner could be on the hook for penalties. It’s a shared venture — and a shared obligation. 

Why This Becomes a Bigger Issue as You Grow 

In a two-person partnership, communication might be easy. But once you have three, four, or more partners, it becomes much more likely that no one is keeping a close eye on deadlines or the accuracy of information being submitted. 

If you rely on an external accountant to file partnership tax return, that helps — but it doesn’t eliminate the need for internal oversight. Someone in the partnership should be responsible for liaising with the accountant, reviewing draft returns, and confirming allocations of profits and expenses are correct. 

Without this, even small mistakes (like misreporting income from a specific client) can create headaches for everyone involved — especially since each partner has to report their individual share of income on their own Self Assessment return. 

The Practical Fix: Shared Visibility, Not Shared Confusion 

Here’s a simple but effective way to avoid trouble: 

• Nominate a partner (formally) to take point on tax — and make sure it’s in writing. 
• Ensure all partners receive a copy of the draft SA800 before it’s submitted. 
• Use cloud-based accounting tools so everyone can access real-time figures. 
• Review the profit split annually and agree on how expenses are being categorised. 

This ensures that while one person may be submitting the return, everyone is informed, involved, and protected.