What happens if I go over the ISA allowance?

Every tax year, you can pay a certain amount into your ISAs without paying tax on the interest or investment growth. Right now, your total ISA allowance is £20,000 per tax year.

You can spread this across different types of ISAs (like Cash or Stocks & Shares), but the combined total of all the "new money" you pay in across all your providers cannot go over that £20,000 limit.

🛑 Wait, have you actually gone over?

Before you report an oversubscription, it's worth double-checking your math. Sometimes it looks like you’ve breached your allowance when you actually haven’t!

What counts as a contribution? In simple terms, a contribution is any "new money" you deposit directly from a regular bank account into your ISA during the current tax year.

The £20,000 limit only applies to these new deposits. The following things do not count towards your allowance:

Interest and investment growth: If your Stocks & Shares ISA goes up in value, or your Cash ISA earns interest, that doesn't count as a new deposit. It's completely fine if your total balance is over £20,000.
Official ISA transfers: Moving money from an old ISA into a new one using an official transfer process doesn't eat into this year's allowance.
Replacing withdrawn money: If you have a "Flexible ISA", you can take money out and put it back in during the same tax year without it counting as a fresh contribution.

📅 What if I went over in a previous tax year?

If your oversubscription happened before 6 April of the current tax year, we aren't able to repair the ISA for you. But don't panic, HMRC can help with these older cases. They will contact you directly (if they haven’t already) to explain the next steps you need to take to fix things.

🛠️ What if I went over in the current tax year?

If you’ve accidentally deposited more than £20,000 across your ISAs since 6 April, the oversubscription can be "repaired." This usually involves removing the extra money you paid in and returning it to your regular bank account.

Who needs to fix it? Repairs are handled by the provider where the extra money actually landed. If you made multiple deposits across different ISAs that pushed you over the limit, you might need to speak to more than one provider.

If any deposits above your allowance went to another provider: You will need to contact them directly to arrange the repair for those specific deposits. We cannot do this for you.
If any deposits above your allowance went into your Monzo ISA: We can help you fix the Monzo side of things.

A quick note on Lifetime ISAs (LISAs): If a deposit that pushed you over your total £20,000 allowance went into a Lifetime ISA (LISA) with another provider, things are slightly different. Because of how LISA bonuses work, you may be able to repair the oversubscription from another ISA instead. If this applies to you, please speak to your LISA provider first so they can confirm the best way to handle it.

If you've confirmed that Monzo needs to handle a repair for you, we just need a few details about your Monzo ISAs and any ISAs you might hold elsewhere. Please complete the ISA oversubscription form so we can get started with your repair.

What happens if I go over the ISA allowance?