(UK) — A proposal to align Capital Gains Tax rates with Income Tax bands would not raise money for the Treasury. IG said on June 29, 2026 that the change would cost the government about £7.8 billion a year.

The comparison at the center of the debate is simple. Income is taxed on earnings such as salary, self-employment profits, and some interest. Capital gains are taxed on profits from selling assets, including shares and second homes. Under the proposal discussed around Wes Streeting’s comments, those two systems would move much closer together, with higher earners paying income-style rates on gains.

For tax year 2026, with returns generally filed in 2027, the reported shift would be sharp. The current higher-rate CGT of 24% would rise to 40%. The current additional-rate CGT of 24% would rise to 45%. That looks, at first glance, like an obvious revenue gain. IG’s analysis says the opposite.

Its breakdown points to a pattern tax officials and investors both watch closely. Basic-rate taxpayers would add only about £10 million. Higher-rate taxpayers would cut revenue by about £3.2 billion. Additional-rate taxpayers would cut revenue by about £4.6 billion. Added together, the annual result is a £7.8 billion loss.

Michael Healy, IG’s managing director for the UK and Ireland, called equalisation “fiscally counterproductive” and said it would cost the Treasury billions of pounds. That view rests on behaviour, not arithmetic alone. When tax on gains rises sharply, people can defer sales, hold assets longer, or change the timing of disposals. The tax rate goes up; the taxable transactions can fall.

That distinction matters for migrants, visa holders, and internationally mobile workers with UK assets. A person can face one tax system on employment income and another on investment gains. In cross-border cases, local rules also interact with treaty claims, residence tests, and foreign tax credits. In the United States, for example, IRS Publication 519 covers alien tax status and Publication 901 covers treaty rules. Those publications do not govern UK CGT, but they shape how a UK disposal may be reported on a U.S. return.

The proposal is also separate from tariffs. Tariffs are taxes on imported goods. Capital Gains Tax is a tax on profit from selling an asset. Both can affect investment and business decisions, but they operate in different parts of the tax system. Treating them as interchangeable leads to bad comparisons.

⚠️ Warning: A higher headline tax rate does not automatically mean higher tax revenue. Real-world receipts depend on how many disposals still happen after the rate change.

The key criteria in this comparison are straightforward. First, ask what type of receipt is being taxed. Salary and wages usually fall under Income Tax rules. Profit from selling shares, property, or another capital asset usually falls under CGT rules. Second, ask which rate band applies. The figures reported in this debate concern higher-rate and additional-rate taxpayers. Third, ask whether the estimate assumes people will keep selling assets at the same pace. That assumption is where revenue forecasts often break down.

A simple example shows the difference. Assume a higher-rate taxpayer realises a £100,000 taxable gain. At 24%, the tax would be £24,000. At 40%, the tax would be £40,000. The gap is £16,000. On paper, the Treasury gains that amount from one transaction. If the investor delays the sale, the Treasury gets £0 this year. Multiply that effect across many disposals, and the revenue picture changes fast.

The same pattern is more pronounced for an additional-rate taxpayer. A £100,000 taxable gain taxed at 24% produces £24,000 of tax. At 45%, the bill becomes £45,000. That is an extra £21,000 on the same gain. A jump of that size gives asset holders a stronger reason to wait, restructure, or dispose of assets under different conditions.

Common mistakes start with mixing up rates and receipts. A higher rate is not the same as a larger tax base. Another mistake is comparing CGT directly with Income Tax without noting the different behaviour each tax triggers. Employees usually cannot choose whether salary is paid this year or next. Investors often can choose when to sell. A third mistake is ignoring cross-border reporting. A migrant who sells a UK asset may still need to report the sale in another country. U.S. filers may need to review Publication 519, treaty rules in Publication 901, and international guidance at IRS international taxpayers.

💡 Tax Tip: Keep purchase records, improvement costs, and sale documents before any disposal. The tax result depends on the gain calculation, not only the headline rate.

Visa holders and new arrivals should separate three questions before filing any return. Which country treats the person as tax resident. Which country taxes the gain first. Whether a treaty or foreign tax credit prevents double taxation. In U.S. practice, that analysis can affect Form 1040, Form 1040-NR, and foreign reporting. Taxpayers with foreign accounts above $10,000 aggregate may also need FBAR reporting, although that is separate from CGT itself.

No filing deadline in this debate changes the usual discipline on recordkeeping and return preparation. If a taxpayer expects a disposal in tax year 2026, documents should be assembled before the sale. Cross-border taxpayers should identify residence status early. Waiting until the return is due can close off elections, relief claims, and foreign tax credit planning.

You are most exposed if you are a higher-rate or additional-rate taxpayer planning a large asset sale, an immigrant or visa holder with reporting duties in more than one country, or an investor assuming that a higher tax rate always means higher Treasury revenue. Review the asset type, confirm residence status, calculate the gain with records in hand, and check whether a treaty claim or foreign tax credit applies before filing.

⚠️ Disclaimer: This article is for informational purposes only and does not constitute tax, legal, or financial advice. Tax situations vary based on individual circumstances. Consult a qualified tax professional or CPA for guidance specific to your situation.