Introduction: Savings Income Tax Rises and the IRS Gives Nothing Back
Savings income tax in Britain rises to 24%, 44% and 49% on 6 April 2027, and an American paying the top rate bears every extra pound personally. The Budget on 28 October 2026 added two points to a rise already legislated, so the additional rate climbs four points in one step from today's 45%. Most commentary stops at the British arithmetic. Yet a US citizen at this income level already has more UK tax than the IRS can credit, so the increase vanishes into a pile of unusable credits.
Higher savings income tax therefore changes the order in which you should rank your cash. Every article we read after the Budget repeated the same advice: use your ISA, shift money to a spouse, buy low-coupon gilts. Each of those moves works differently once a US return sits alongside the British one, and two of them are worth far less than they look. At TaxYork, we prepare both returns for wealthy Americans in London, and this guide ranks the realistic homes for sterling and dollar cash using our own after-tax figures.
Savings Income Tax in One Paragraph
Savings income tax is the UK income tax charged on interest and similar returns under its own set of rates, separate from the rates on salary and dividends. The HMRC tax information note published on 29 October 2026 confirms that the new rates apply from the 2027 to 2028 tax year across the whole UK, including Scotland. Legislation will follow in Finance Bill 2026-27, so treat the figures as announced rather than enacted until that Bill passes.
Who This Guide Is For
We wrote this for US citizens and green card holders who live in Britain and hold meaningful cash outside a pension. Typical readers include investment bankers with deferred bonuses in deposit, founders holding sale proceeds, and dual nationals with sterling savings they have never reported in America. If your interest sits above the top of the higher-rate band, every figure here applies to you directly. Below that level, the principles still hold, although the numbers soften.
What the Budget Changed on Savings Income Tax
Three facts about savings income tax matter before any planning starts: the rates, the allowances, and where interest sits in your income. All three shape your bill more than the headline suggests.
The Rates, the Allowances and What Survived
Today, savings income tax runs at 20%, 40% and 45%. The Finance Act 2026 had already set 22%, 42% and 47% for 2027 to 2028, and the Budget lifted those to 24%, 44% and 49%, as the ICAEW summary of the Budget measure records. Salary stays at 45% at the top. Dividends stay at 39.35%, and capital gains stay at 24%. Consequently, savings income tax becomes the heaviest charge a wealthy British resident can face on any return.
The Personal Savings Allowance survives unchanged at £1,000 for basic-rate payers and £500 for higher-rate payers. Additional-rate payers still receive nothing. The £5,000 starting rate also survives, although salary above a low threshold removes it, so it will not help anyone reading this. Separately, the Government dropped its earlier plan to cut the cash ISA limit, so the £20,000 ISA allowance applies in full for all adults.
Where Interest Sits in Your Income
The order of taxation in section 16 of the Income Tax Act 2007 puts savings above salary but below dividends. As a result, your salary fills the bands first, and interest lands on top of it. For a banker on £400,000, every pound of interest is an additional-rate pound. Moreover, income within savings income tax counts towards adjusted net income, so a large deposit can push a lower earner through the £100,000 taper and lose the personal allowance as well.
What Falls Inside the New Rates
Savings income tax reaches further than bank statements suggest. It catches gilt coupons, corporate bond interest, Treasury bill discount, and interest distributions from bond funds under section 378A of the Income Tax (Trading and Other Income) Act 2005. In addition, section 18 of the Income Tax Act 2007 treats chargeable event gains on life insurance bonds as savings income. That detail surprises clients who bought an offshore bond specifically to escape savings income tax.
Many HNW clients also hold cash in dollars. For a UK resident, interest from a New York account is foreign savings income, so savings income tax at 49% reaches it too unless you are inside the four-year regime discussed below.
Why the US Credit Cannot Absorb Higher Savings Income Tax
Here is the gap in the published guidance. Generic expat articles reassure you that a higher UK tax simply produces a larger foreign tax credit. At the top of the income scale, that reassurance is wrong.
The Credit Is Capped at the US Tax
The foreign tax credit limitation in section 904 of the Internal Revenue Code caps your credit at the US tax on that foreign income. The top federal rate is 37%. Therefore, once savings income tax reaches 45%, you already have eight points of surplus credit. Raising the charge to 49% produces twelve points of surplus. Your US bill does not fall by a cent, because it already stood at zero.
In practice, this makes the rise in savings income tax a pure cost for you. A lower-income American whose US rate exceeds the UK rate might see the IRS absorb part of a rise, as the extra UK tax would simply replace US tax. You get no such cushion. On £5 million of deposits earning 4%, the extra four points cost £8,000 a year, all of it final. Surplus credits carry back one year and forward ten, but they rarely find a home in those years either.
The High-Tax Kick-Out Moves the Surplus
Interest normally falls in the passive category on Form 1116. However, passive income taxed abroad above the top US rate gets reclassified into the general category under the high-tax rule, and Treasury Regulation 1.904-4 sets out how the income is grouped for that test. Interest carrying UK savings income tax generally moves across to sit alongside your salary, where excess credits have usually piled up already.
This matters for one reason that most advisers overlook. Untaxed income, such as ISA interest or a gilt redemption gain, stays behind in the passive category. Consequently, the surplus from your bank interest cannot shelter it. Clients often assume their mountain of UK credits covers everything. In our experience, it covers almost nothing that Britain leaves untaxed.
The 3.8% Charge the Credit Never Reaches
The net investment income tax adds 3.8% to interest once modified adjusted gross income passes $200,000, or $250,000 for joint filers. Because section 1411 sits outside the income tax chapter of the Code, foreign tax credits do not reduce it. On 31 August 2026 the Federal Circuit reversed taxpayer wins in Bruyea and Christensen, holding that the Canadian and French treaties do not change that result. Those rulings did not address the UK treaty, but we would not plan on a different outcome. You report the charge on Form 8960.
Taken together, UK interest in an American's hands costs 52.8% from April 2027: 49% to HMRC and 3.8% to the IRS. No other common investment return comes close. By comparison, a UK dividend costs roughly 43.15%, and a capital gain roughly 27.8%.
Ranking Your Cash Under the New Savings Income Tax
We built the ladder below for an additional-rate American holding £1 million, assuming a 4% gross yield unless stated. These are our own illustrative figures, not market quotes, and they ignore currency movements.
UK Deposits: The Baseline of 52.8%
A taxable deposit earns £40,000. HMRC takes £19,600 in savings income tax, the IRS takes £1,520, and you keep £18,880. That is your baseline, and everything else should beat it. Note that a non-American in the same bracket keeps £20,400, so your passport costs you about £1,520 a year per million.
US Treasury Bills: Equal Only If You Claim the Treaty
Treasury bills look like home turf, but they carry the worst downside on this ladder. Treasury interest is US-source, so the default foreign tax credit against it is nil. Without relief, you pay 37% to the IRS on top of 49% to HMRC, plus the 3.8%, and keep just £4,080. Under Article 24(6) of the US-UK income tax treaty, you can re-source the interest to Britain and restore the credit, which brings you back to the £18,880 baseline. You must make that claim on a separate Form 1116, and we cover the mechanics in our guide to US Treasury bills for Americans in Britain.
Municipal Bonds: A Break-Even You Can Calculate
Section 103 exempts municipal bond interest from federal income tax and from the 3.8% charge. Britain ignores that exemption and charges savings income tax in full. So your cost is 49%, against 52.8% on a deposit. To match the baseline of £18,880, a municipal bond must yield about 3.70% when a taxable deposit yields 4%. At 3.3% it nets only £16,830, so it loses. Run that break-even on any quote before you buy, and add the dollar exposure to your thinking.
Low-Coupon Gilts: Good, Though Far Less Than You Have Heard
Low-coupon gilts lead nearly every British article on this Budget, because section 115 of the Taxation of Chargeable Gains Act 1992 exempts the redemption gain from UK tax. Take a gilt with a 0.5% coupon and a 3.5% annual pull to par, as available through the UK Debt Management Office market. A British resident pays 49% on £5,000 of coupon and keeps £37,550 in total.
An American keeps far less, because section 1276 treats accrued market discount as ordinary interest. You owe 37% on £35,000 of discount, with no UK tax to credit against it and no help from your surplus credits, because they sit in a different category. After the 3.8% charge on the whole £40,000, you keep £23,080. That still beats a deposit by £4,200 a year per million, so gilts remain the best large-scale option on this ladder. However, your edge is roughly a quarter of what your British colleague enjoys. A separate currency gain or loss under section 988 can then add to or reduce the result. Our UK gilts guide for Americans covers that charge in detail.
ISAs and Premium Bonds: Real but Small
A cash ISA removes savings income tax on £20,000, which saves a British additional-rate saver about £392 a year at 4%. For you, the same £800 of interest stays fully taxable in America at 40.8%. Your saving against a deposit shrinks to about £96. A cash ISA remains worth having, but it does not solve anything, and it creates US reporting. The same logic applies to Premium Bonds, capped at £50,000, whose prizes are tax-free only in Britain.
Other Moves to Test Against Savings Income Tax
Several ideas circulating since the Budget need a US reality check. Some work; others make matters worse.
Retaining Cash in Your Company
Founders ask whether to leave money in their company at 25% corporation tax rather than draw it and pay 49% savings income tax. Taken alone, that looks attractive. If you extract the money later, however, £40,000 of interest loses £10,000 to corporation tax and £11,805 to dividend tax, plus £1,140 of net investment income tax. That totals 57.4%, which is worse than a deposit in your own name. Retention therefore only pays where you truly intend to reinvest. Meanwhile, interest in a US-controlled UK company is typically subpart F income, so you need the high-tax exception in section 954(b)(4) to avoid a current US inclusion. At 25%, you clear the 18.9% test, but only if you make the election.
Shifting Cash to a Spouse
Moving deposits to a lower-rate British spouse cuts savings income tax, and many post-Budget checklists recommend it. For a mixed-nationality couple, it also moves money outside the American's US tax net from that point. Nevertheless, the IRS applies an annual limit to transfers to a non-citizen spouse, and larger transfers carry a reporting duty. Joint accounts add a further wrinkle, because the two countries can split the interest differently. Check both sides before you move anything substantial.
The Four-Year Foreign Income Regime
New arrivals have the cleanest answer available. Under the four-year foreign income and gains regime, a qualifying new resident pays no savings income tax on foreign interest. So a Treasury portfolio held in New York escapes the 49% for up to four years, while US tax applies at 40.8% with no credit needed. Sterling deposits in London do not qualify, because their interest arises in Britain. Consequently, keep overseas cash overseas during those years and plan your exit from the regime well before year five.
Pension Contributions
Pension funding removes money from the reach of savings income tax and grows it free of UK tax. For most Americans, Article 18 of the treaty can also defer the US tax on growth. However, the annual allowance tapers sharply at high incomes, so this rarely shifts more than a modest sum. Treat it as a useful supplement rather than a home for a large deposit.
Timing Your Interest Before the 6 April 2027 Change
Because savings income tax jumps on a single date, when you receive interest suddenly carries a price tag. HMRC generally taxes bank interest when it is paid or credited, not as it builds up.
Fixed-Term Deposits and Rolled-Up Interest
A fixed-term bond that pays everything at maturity makes this concrete. Suppose £96,000 of rolled-up interest falls due. Maturing in March 2027, it bears savings income tax at 45%. Maturing in May 2027, it bears 49%, which costs £3,840 more on the same cash. So check maturity dates now, and ask your bank about early access terms before you assume the penalty outweighs the saving. Our guide to fixed-rate bonds for Americans explains how the US accrues the same interest each year regardless. Note that post predates this Budget, so read its UK top rate as 49% from April 2027.
Treasury Bills and Short-Dated Holdings
The same logic applies to a Treasury bill, where savings income tax falls on the discount when you redeem or sell. For a twelve-month bill bought now, a maturity on the wrong side of 5 April costs an additional four points on the whole discount. Where you are laddering bills, stagger your purchases to mature before that date, then reinvest in the following tax year.
The Credit Timing Trap in the First Year
US and UK tax years also fail to match. Under Treasury Regulation 1.905-1, an accrual-method taxpayer generally treats UK tax for the year ending 5 April 2028 as accruing in the US year 2028. A cash-method filer claims it when paid, which is often January 2029. That means your 2027 US return reports interest taxed at 49% from April onward, yet it may draw its credit from an earlier 45% year. While UK rates exceed 37%, the gap is usually harmless. It bites when interest spikes in one year, such as the year you bank sale proceeds, so model large receipts before they arrive.
Your Decision Sequence Under the New Savings Income Tax
We use a five-stage sequence with clients, and it runs in this order for a reason. First, confirm your US position: if you have unfiled returns or a missed FBAR, fix that before you restructure anything, since moving accounts creates a fresh paper trail. Second, split your cash by purpose, because money needed within two years cannot accept gilt price risk or dollar risk.
Third, check for the four-year regime, since it beats every other option while it lasts. Fourth, for long-horizon sterling cash, price low-coupon gilts on your true American after-tax yield, then compare municipal bonds against the 3.70% break-even if dollars suit you. Fifth, review every maturity date falling within six months after 6 April 2027. Do this in order, and you avoid the common mistake of buying a product before knowing how the IRS will treat it.
The Reporting That Follows Any Move
Every home on this ladder carries US reporting. Foreign accounts over $10,000 in aggregate require a Report of Foreign Bank and Financial Accounts. Form 8938 also applies above its higher thresholds for filers abroad, as the IRS comparison of Form 8938 and the FBAR explains. Moving deposits into a UK money market fund is the classic own goal, because the IRS usually treats that fund as a PFIC. See our note on money market funds for Americans before you accept any cash sweep your private bank proposes.
HMRC's Interest Data Is Improving
Higher savings income tax also makes HMRC keener to collect. Its technical consultation on third-party data sets out rules under Schedule 23 to the Finance Act 2026. From 6 April 2028, banks must report interest on a set schedule and collect and verify customers' tax references. Therefore, missed UK tax returns on interest become easier to detect, and accounts opened under old details will surface. Correct any savings income tax you owe before that system begins.
Case Study: £2.4 Million of Sale Proceeds on Deposit
Consider an illustrative client: a US citizen in London with a £600,000 banking package and £2.4 million in sterling deposits from a business sale. At 4%, the deposits pay £96,000 a year.
The Position If Nothing Changes
In 2026/27, HMRC charges 45%, or £43,200. In 2027/28, savings income tax takes £47,040, which is £3,840 more. The IRS adds £3,648 of net investment income tax, and regular US tax is nil after the credit. Total tax reaches £50,688, leaving £45,312. That is the 52.8% in real money. Meanwhile, a further £11,520 of stranded credit joins a pile that already cannot be used.
The Restructured Position
The client needs £900,000 within two years for a house purchase, so that stays in deposit and maturities move ahead of 6 April 2027. The remaining £1.5 million moves into low-coupon gilts held to redemption. On our assumptions, those gilts net £34,620 a year, against £28,320 on deposit, which gains £6,300 a year. Over five years that comes to £31,500, before currency effects and dealing costs.
What the Client Did Not Do
The client did not buy municipal bonds, because the quoted 3.3% fell short of the 3.70% break-even. Nor did the client route the cash through a company, as extraction would have cost 57.4%. Finally, the client kept a £20,000 cash ISA, while accepting that it saves only £96 a year on US-adjusted figures. A British colleague with identical wealth would have made quite different choices, which is the whole point. Savings income tax planning copied from British commentary would have overstated this client's gilt benefit by about four times.
How TaxYork Can Help With Savings Income Tax
Our team handles US tax returns for expats and the matching UK return for clients with substantial cash, so one team sees both sides of every decision. We calculate your real after-tax yield on each option, prepare Form 1116 and Form 8960, make the Article 24(6) claim where Treasury interest requires it, and handle FBAR and Form 8938 filings. Where accounts have gone unreported, we prepare the US and UK catch-up work before any restructuring begins. For wider relocation and investment structuring, see our cross-border tax planning service.
Conclusion: Rank Your Cash on American Numbers
The new savings income tax rates turn interest into the most expensive income a wealthy UK resident can earn. For an American, the rise is entirely final, because the US credit was already exhausted at 45%. Deposits now cost 52.8%, and the popular fixes deliver less than advertised: ISAs save pennies, gilts retain perhaps a quarter of their British edge, and company retention can leave you worse off. Therefore, check your maturity dates before 6 April 2027, price each option on American numbers, and put your filings in order first.
Contact Us
If you hold substantial cash in Britain and want it ranked on your actual numbers, book a consultation with our team. You can also email hello@taxyork.com or call 020 3488 8606.
Disclaimer
This article provides general information for educational purposes only and does not constitute tax, legal or financial advice. The rates described were announced at Budget 2026 and remain subject to Finance Bill 2026-27. The figures are illustrative, and your own position depends on your facts. Please take personalised professional advice before acting.