Anglo American (LSE:AAL) was down about 2.8% by midday on Tuesday as copper fell to a seven-week low, part of a Mining sell-off that helped end the FTSE 100's four-day winning run.

By lunchtime on Tuesday 3 November, the message from the metals market was hard to miss. Copper had dropped to its lowest level in seven weeks, industrial metal miners had slumped to their weakest in almost four months, and Anglo American (LSE:AAL) was trading about 2.8% lower, according to midday reports from Reuters carried by Share Talk. The diversified miner went on to fall with the rest of the sector as the session closed.

The damage was visible in the headline numbers. The FTSE 100 ended the day at 10,638.43, down 122.90 points or 1.14%. It was the index's steepest one-day fall in a month, and it brought to a close a sequence of four straight daily gains. The FTSE 350 basic resources index lost 2.6% over the session.

Anglo American did not issue company-specific news in the sources used for this article. Its move was a reaction to the metal market rather than to anything the company said, which makes it a good example of how sector-wide forces can dominate an individual share price on a given day.

Reading the copper signal

Alliance News reported that copper fell 2.5% on Tuesday. That is a substantial one-day move for a major industrial metal, and the seven-week low it produced added to a sense that investors were retreating from growth-sensitive assets.

Copper is often treated as a gauge of economic health because it is so widely used in building, electrical systems, energy networks and manufacturing. When investors become more cautious about growth or about the cost of money, they may expect Demand for the metal to soften, and that view can show up quickly in prices. The fact sheet used here does not pin Tuesday's slide on any single cause, so it is better to describe the backdrop than to claim a precise trigger.

That backdrop was uneasy. Crude Oil slid about 2% on Tuesday in volatile trade, according to Reuters, after a fall of roughly 7% on Monday, as investors weighed talks aimed at ending the wars in Ukraine and Iran. Reuters also noted that elevated oil prices have fuelled Inflation fears and that many central banks have raised interest rates. In the UK, a 25 basis point increase from 3.75% to 4% is widely expected from the Bank of England on Thursday 5 November.

Why a diversified miner still feels it

Anglo American is a diversified mining group, meaning it produces more than one commodity. In general, Diversification can soften the impact of a fall in any single metal, because Earnings come from several sources. But copper is one of the most important industrial metals in global markets, and when it moves sharply, many large miners tend to be pulled along, partly because investors often buy and sell the sector as a group.

That may help explain why the moves across the FTSE 100's big miners were so similar on Tuesday. Glencore (LSE:GLEN) closed 2.8% lower, matching Anglo American's midday decline, while Antofagasta (LSE:ANTO), a more concentrated copper producer, fell 3.5%. A common thread ran through the sector, even if the size of each move varied with each company's mix of operations.

It is worth being careful with the numbers. The 2.8% figure for Anglo American comes from midday reporting, and the fact sheet does not record its closing move. Closing market reports described the company as falling with miners as the session ended, but anyone comparing it precisely with closing figures for other companies should keep that timing difference in mind.

For illustration only, if a hypothetical holding worth £1,000 fell by 2.8%, it would lose £28 in value, leaving £972. That arithmetic is shown simply to make a percentage move concrete.

There is also an index-level angle. FTSE 100 weightings are based on market value, so when several large miners fall together, the combined effect on the headline index can be considerable even if no single company dominates. On Tuesday, the basic resources sector and the banks between them supplied much of the day's decline.

A wider risk-off session

Miners were not the only drag. The FTSE 350 banks index fell 1.6% ahead of the Bank of England decision, and HSBC (LSE:HSBA), down 2.0%, was the biggest approximate drag on the FTSE 100 in points terms. Precious metal miners lost about 2.7% to a three-month low at midday, and aerospace and defence shares were down about 1.2% at the same stage.

The selling grew heavier as the day went on. The index stood at about 10,705 early in the morning and around 10,687.72 at midday, before finishing at 10,638.43. The FTSE 250, with less exposure to large international miners, fell a more modest 0.5% to 24,674.91.

The US midterm elections were also taking place on Tuesday, with all 435 House seats and 35 Senate seats being contested. Reuters said a Democratic showing was regarded as priced in.

Key dates to watch

Wed 4 Nov:Eurozone inflation figures, expected at 3.9%.

Thu 5 Nov:Bank of England MPC decision; a 25bp rise to 4% is widely expected.

Fri 6 Nov:US October jobs report.

Thu 12 Nov:ONS first quarterly GDP estimate for July–September 2026, at 7:00am.

Tue 1 Dec:FTSE Russell December review market-cap data cut-off.

The bottom line

Copper's slide to a seven-week low set the tone for Anglo American on Tuesday. The diversified miner was down about 2.8% by midday and fell with the sector into the close, alongside Glencore and Antofagasta. Nothing in the available material points to a company-specific reason; the move reflected a sector caught up in worries about inflation, interest rates and economic momentum. With Central Bank decisions and key economic data arriving over the coming days, the copper price is likely to remain an important influence on how Anglo American trades within the FTSE 100.