Why Is the UK Stock Market Down Today? FTSE 100 Slips as Middle East Tensions and Higher Oil Prices Weigh on Sentiment

UK stocks opened slightly lower today with the FTSE 100 down 0.14% as Strait of Hormuz tensions, rising oil prices and caution ahead of US inflation data weighed on investor sentiment.

By: Nisha Srivastava
Last Updated: August 12, 2026 14:13:27 IST

UK Stock Market Today (August 12):  UK stock market opened slightly lower on Wednesday, with the FTSE 100 down around 0.08%-0.1%, as renewed uncertainty over the US-Iran standoff and the Strait of Hormuz weighed on sentiment. Investors were also cautious ahead of the latest US Consumer Price Index (CPI) data, which could influence expectations for the Federal Reserve’s interest-rate path.

The geopolitical situation remained a key market concern, with Iran maintaining that the Strait of Hormuz would remain closed unless its conditions were met. The uncertainty has kept energy prices elevated, with Brent crude trading around $89.49 a barrel, raising concerns that higher energy costs could add to inflationary pressures and weigh on global economic growth.

London Stock Exchange Down Today

London stocks are trading marginally down, with the FTSE 100 losing approximately 0.1%, to trade at 10,832.46. Sentiment in the markets is rather cautious amid expectations of an important release of inflation numbers from the United States along with some geopolitical concerns in the Middle East.

UK Stock Market Today: FTSE 100 Market Snapshot

The FTSE 100 Index is trading at 10,829.23, down 0.14% (-14.96 points) as of Wednesday morning. The FTSE 100 is trading lower as renewed uncertainty surrounding the US-Iran standoff and the Strait of Hormuz weighs on investor sentiment. European equities also opened mostly lower, while Brent crude traded close to $90 a barrel, raising concerns about renewed inflationary pressure.

  • Opening Value: 10,844.19
  • Daily High: 10,849.43
  • Daily Low: 10,821.36
  • Previous Close: 10,844.19

UK Stock Market Today (August 12): Major FTSE Indices Market Performance

The FTSE 100 declined 14.96 points to 10,829.23, while the FTSE 350 fell 6.12 points to 5,906.45 and the FTSE All-Share slipped 5.86 points to 5,842.04. Meanwhile, the FTSE 250 gained 43.57 points to 24,843.32. The FTSE AIM UK 50 rose 18.77 points to 4,308.76, while the FTSE AIM 100 advanced 16.90 points to 3,755.98 and the FTSE AIM All-Share climbed 2.78 points to 802.35.

Why Is the UK Stock Market Down Today? (August 12, 2026)

UK equities markets are weaker today due to a rising threat of a US and Iran clash in the Strait of Hormuz and investor nervousness amid important US inflation figures. Today, the FTSE 100 opened down by about 0.1% at 10,832 points, following weakness in many international and European markets.

Key Factors Behind the Decline

  • Strait of Hormuz Tensions: Growing concerns over shipping security through the Strait of Hormuz have increased geopolitical risk and pushed Brent crude towards $89 a barrel. Higher energy costs could revive inflationary pressures and increase uncertainty for businesses and investors.
  • Caution Ahead of US CPI Data: Investors are awaiting the latest US Consumer Price Index (CPI) figures. A stronger-than-expected inflation reading could push bond yields higher and reduce expectations for Federal Reserve rate cuts, potentially putting additional pressure on equities.
  • Weakness in Key Sectors: The FTSE 100 has also faced pressure from insurance and industrial stocks. Legal & General came under pressure following broker downgrades linked to concerns over valuations and solvency, while Spirax fell after maintaining its full-year guidance despite reporting stronger first-half results.
  • Rising Bond Yields: Higher oil prices have renewed concerns about global inflation, contributing to an increase in government bond yields. The UK 10-year gilt yield has moved back towards the 5% level, potentially making fixed-income assets more attractive relative to equities.

UK Stock Market Down Today: What Should Investors Watch Next?

  • Inflation and wage figures from the UK.
  • Any new information provided by the Bank of England.
  • Earnings reports from FTSE-listed firms.
  • Fluctuations in oil, copper, and gold prices.
  • Yields on global bonds and US markets performance.
  • Geopolitical events influencing investors’ sentiment.

Disclaimer: The information provided in this article is for informational purposes only and does not constitute financial advice. The Sunday Guardian suggests that readers consult with a certified financial advisor before making any investment or money-related decisions. The stock market involves significant risk.

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