Introduction
On 16 September 2026 the US Federal Reserve raised interest rates. The Fed rate hike took the target range for the federal funds rate to 3.75% to 4.00%, the first increase since July 2023.
That matters more to a UK investor than it sounds. If you hold a global index fund in a Stocks and Shares ISA or a SIPP, most of your money sits in the United States. This article covers what the Fed did, why, and which parts of it reach a UK portfolio.
This article is for information and education only. It is not financial advice or a personal recommendation. The value of investments can fall as well as rise and you may get back less than you invest. Tax treatment depends on your individual circumstances and may change in future. If you are unsure, seek advice from an FCA regulated adviser.
Quick Answer: What The Fed Rate Hike Changed
The Federal Reserve raised its target range by 0.25 percentage points to 3.75% to 4.00%, its first rise since July 2023, citing inflation still above target. For UK investors the effect is indirect but real, because the United States makes up most of a typical global fund.
What The Fed Actually Did
The Federal Open Market Committee raised the target range for the federal funds rate by a quarter of a percentage point, from 3.50% to 3.75%, up to 3.75% to 4.00%. The decision was unanimous on a 12 to 0 vote and took effect on 17 September 2026.
Alongside it the Board lifted the rate paid on reserve balances to 3.90% and the primary credit rate to 4.00%, the plumbing rates that keep the federal funds rate inside its range.
The direction is the story. In July the Committee held rates, though three members already preferred an increase. In September the whole Committee moved together.
First Rise In Over Three Years
The Federal Reserve had not raised rates since July 2023. Every move in between was a cut or a hold, so this is a change of direction.
Why The Fed Raised Rates
Inflation. US consumer prices rose 3.4% in the year to August 2026, up 0.4% on the month, although core inflation excluding food and energy was softer at 2.4%. The Committee said the increase was intended to support a “timelier return” to its 2% goal.
The Fed also published updated projections. The median forecast puts the federal funds rate at 4.1% at the end of both 2026 and 2027, with PCE inflation at 3.7% for 2026.
That median sits a little above the new range, implying members on balance expect roughly one further quarter point rise this year. A projection is not a promise.
Who The Fed Rate Hike Actually Affects In The UK
Almost certainly you, if you own a global tracker.
The MSCI World Index, which many popular global funds follow or closely resemble, had a 72.14% weight in the United States at 31 August 2026, against 3.53% in the United Kingdom. Nobody chose that deliberately. It is what happens when an index weights companies by size.
So a US rate decision is not foreign news for a UK investor. It concerns roughly seven pounds in every ten of a global fund.
A global tracker holds roughly twenty times as much in the United States as in the United Kingdom, which is why a US rate decision reaches a UK portfolio directly.
Other developed markets figure is the residual after the United States and the United Kingdom. Source: MSCI World Index factsheet, 31 August 2026. Verified 17 September 2026.
What A Fed Rate Hike Does To Your ISA And SIPP
Three mechanisms are worth understanding, and none is a prediction about next week.
Company valuations. A share price reflects what investors will pay today for profits earned in the future. When rates rise, those future profits are discounted more heavily, which tends to weigh on valuations. The effect is felt most by companies whose profits sit furthest out, which in practice means fast growing technology firms.
Bonds and gilts. Higher policy rates generally push bond yields up and bond prices down, and government bond markets move together across borders to a degree. If you hold a bond fund, that is the channel to watch, and we covered the UK end of it in long dated gilt yields.
Cash. A US rate change does not move UK savings rates. Those follow Bank Rate, set separately by the Bank of England.
The Currency Effect UK Investors Often Miss
This is the part that catches people out, and it is specific to investing from Britain.
Most global and US index funds sold here are unhedged, so you own dollar assets through a fund priced in pounds. Your return has two moving parts: what the shares did, and what the pound did against the dollar.
Higher US rates tend, other things being equal, to support the dollar, because dollar deposits pay more. If the dollar strengthens against the pound, the sterling value of your US holdings rises even if the shares go nowhere. It works in reverse too, which is why a UK investor and a US investor can hold the same fund in the same week and report different returns.
Neither outcome is something to act on. It is something to understand, so a move in your balance is not mistaken for a move in the companies themselves.
Two Moving Parts, Not One
An unhedged global fund gives a UK investor both the share price return and the currency return. Check a fund factsheet for the word hedged before assuming which one you hold.
What To Watch Next
The Bank of England is the near term event for UK savers. Bank Rate stood at 3.75%, a level set on 30 July 2026, with the September decision due at midday on 17 September 2026. That announcement had not been made when this was written, so check the Bank of England site for the outcome.
The backdrop differs on each side of the Atlantic. UK CPI rose to 3.1% in the year to August 2026, with core at 2.6%. US headline inflation is higher at 3.4%, but US core is lower at 2.4%.
| United States | United Kingdom | |
|---|---|---|
| Policy rate | 3.75% to 4.00% | 3.75% Bank Rate |
| Last change | Raised 0.25 points, 16 September 2026 | Set 30 July 2026 |
| Direction of last move | Up, first rise since July 2023 | Held |
| Headline inflation | 3.4% CPI, August 2026 | 3.1% CPI, August 2026 |
| Core inflation | 2.4% | 2.6% |
Sources: Federal Reserve, US Bureau of Labor Statistics, Bank of England and ONS. Verified 17 September 2026.
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What To Ignore
The first day of market reaction. Prices move sharply around a rate decision and often unwind, and one session tells you little about the next decade. The evidence on trading around such events is not encouraging, as we set out in time in the market versus timing the market.
Anyone confident about where rates go next. The Committee publishes a range of views precisely because its members disagree.
And the urge to restructure a long term plan around one meeting. The arithmetic that does the heavy lifting is contributions and time, as our compound interest calculator shows.
Key Takeaways
The Fed Raised Rates For The First Time Since July 2023
The target range went up 0.25 points to 3.75% to 4.00% on 16 September 2026, on a unanimous 12 to 0 vote.
It Was About Inflation
US headline CPI was 3.4% in the year to August 2026. The Committee said the rise was meant to support a timelier return to its 2% target.
Most Of Your Global Fund Is American
The MSCI World Index held 72.14% in the United States at 31 August 2026, against 3.53% in the United Kingdom. A US rate decision is not foreign news.
UK Savings Rates Follow Bank Rate, Not The Fed
Cash ISA and savings rates track the Bank of England. Bank Rate was 3.75%, set on 30 July 2026, with a decision due 17 September 2026.
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Frequently Asked Questions About The Fed Rate Hike
Sources
Sources: FOMC statement, 16 September 2026; Federal Reserve implementation note; FOMC Summary of Economic Projections; FOMC statement, 29 July 2026; US Bureau of Labor Statistics, CPI August 2026; Bank of England Bank Rate; ONS Consumer price inflation, August 2026; MSCI World Index factsheet, 31 August 2026. All figures verified 17 September 2026.
This article is for information and education only. It is not financial advice or a personal recommendation. The value of investments can fall as well as rise and you may get back less than you invest. Tax treatment depends on your individual circumstances and may change in future. If you are unsure, seek advice from an FCA regulated adviser.
