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Best ISA Interest Rates in the UK: How XTB Compares

With interest rates changing and more people looking for tax-efficient ways to grow their money, Individual Savings Accounts (ISAs) continue to play an important role in financial planning for UK savers and investors.

 

XTB now offers both a Flexible Cash ISA and a Flexible Stocks & Shares ISA, giving clients the freedom to choose how they want to use their annual ISA allowance. Whether you prefer to keep your money in cash and earn tax-free interest, or invest directly in global financial markets, XTB provides the flexibility to build an ISA strategy that suits your financial goals.

 

XTB is offering one of the best interest rates on both Cash ISA and Stocks and Shares ISA. 

With interest rates changing and more people looking for tax-efficient ways to grow their money, Individual Savings Accounts (ISAs) continue to play an important role in financial planning for UK savers and investors.

 

XTB now offers both a Flexible Cash ISA and a Flexible Stocks & Shares ISA, giving clients the freedom to choose how they want to use their annual ISA allowance. Whether you prefer to keep your money in cash and earn tax-free interest, or invest directly in global financial markets, XTB provides the flexibility to build an ISA strategy that suits your financial goals.

 

XTB is offering one of the best interest rates on both Cash ISA and Stocks and Shares ISA. 

As part of a current promotion, XTB is offering up to 6% AER interest on uninvested GBP balances held within an ISA, helping new clients earn a competitive return even while their cash is waiting to be invested. New clients can also receive a free share when opening an account, adding an extra incentive to get started. Please see T&Cs here. 

In an increasingly competitive ISA market,  with platforms such as Trading 212, Plum, eToro, and Moneybox offering their own solutions, XTB stands out by combining several key benefits in one place. The ability to earn interest on cash balances, invest in stocks and ETFs with commission-free trading up to 100k EUR, and take advantage of promotional offers makes XTB a compelling choice for UK investors looking to make the most of their ISA allowance.

Interest on Funds

One standout feature of the XTB ISA is the promotional interest rate on uninvested cash balances. New investors can earn up to 6% AER for the first 90 days on new ISA accounts opened between 1 March and 30 April 2026.

  • Standard variable rate: 4% AER
  • Promotional boost: +2%
  • Total promotional rate: 6% AER

Interest is calculated daily and paid monthly, allowing ISA holders to earn a return on cash that has not yet been invested. After the promotional period, balances continue to earn the standard rate of 4% AER.

Tax-Efficient Investing with an ISA

Like all ISAs in the UK, XTB’s ISA structure provides valuable tax benefits:

  • Tax-free capital gains
  • Tax-free dividend income
  • No tax on interest earned

UK investors can contribute up to £20,000 per tax year across their ISA accounts. By combining this tax-efficient wrapper with interest on uninvested cash, XTB enables investors to earn returns while planning their investment allocations.

Commission-Free Investing with XTB

XTB’s Stocks & Shares ISA provides access to thousands of global markets, helping investors grow their portfolios without high fees. Key features include:

  • 0% commission on stocks and ETFs within a monthly trading volume of €100,000
  • No account opening fees
  • No maintenance fees 
  • Access to 8,500+ global stocks and ETFs

This structure reduces costs compared to traditional brokerage platforms that charge per-trade fees, making XTB a strong contender for commission-free ISA investing.

Free Share Promotion for New Clients

New ISA clients can receive a free share upon opening an account and making a deposit. Eligible investors can choose from a selection of five available stocks, adding an immediate incentive to start investing with XTB.

How XTB Compares with Other ISA Platforms

The UK ISA market includes several popular platforms, including Trading 212, Plum, Etoro, and Moneybox. While traditional brokers may charge platform or trading fees, fintech platforms like XTB focus on lower costs, app-based investing, and flexible options.

XTB uniquely combines:

  • Commission-free trading on global markets
  • Interest on uninvested cash balances
  • Tax-efficient ISA benefits

This makes it appealing for investors holding cash before allocating funds or seeking a flexible and cost-efficient ISA.

All data correct as of 2 March 2026.  All rates are based on AER and relate to Cash ISAs only.

Additional Features of XTB ISAs

XTB also offers several additional features to enhance investor flexibility:

  • Flexible withdrawals: Withdraw and replace funds within the same tax year without affecting your ISA allowance (flexible ISA).
  • Multi-currency accounts: Hold balances in GBP, EUR, and USD for simplified international investing.
  • Access to global markets: Trade thousands of companies and ETFs worldwide from a single platform.

Why Investors May Choose XTB

XTB’s ISA offer appeals to investors looking to:

  • Maximise tax-efficient returns
  • Manage cash before investing
  • Keep investment costs low

By combining interest on uninvested balances, commission-free trading, and ISA tax benefits, XTB provides flexibility suitable for both new and experienced investors.

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This content has been created by XTB S.A. This service is provided by XTB S.A., with its registered office in Warsaw, at Prosta 67, 00-838 Warsaw, Poland, entered in the register of entrepreneurs of the National Court Register (Krajowy Rejestr Sądowy) conducted by District Court for the Capital City of Warsaw, XII Commercial Division of the National Court Register under KRS number 0000217580, REGON number 015803782 and Tax Identification Number (NIP) 527-24-43-955, with the fully paid up share capital in the amount of PLN 5.869.181,75. XTB S.A. conducts brokerage activities on the basis of the license granted by Polish Securities and Exchange Commission on 8th November 2005 No. DDM-M-4021-57-1/2005 and is supervised by Polish Supervision Authority.

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