UK Market Breakdown: Oil Round Trip, $9bn IPO, Week of 21 September 2026

London spent the first three sessions of this week doing more or less whatever the oil price told it to. Monday opened with Brent falling almost 4% back below $100 a barrel on hopes of renewed US-Iran diplomacy, and the FTSE 100 closed 79.88 points higher at 10,739.01, a gain of 0.75%. Tuesday handed some of that back: the index slipped 30.68 points to 10,708.33, or 0.29%, as another awkward set of public borrowing figures landed and crude crept back above $100. Wednesday brought a third turn, with Brent settling 3.86% higher at $103.08 and the oil majors pulling the index up 0.1% to close at 10,719.

Net of all that shoving, the FTSE 100 is around 0.6% above Friday's 10,659.13 close — a small number concealing a great deal of movement underneath it.

The week's most consequential piece of London news had nothing to do with the index level. On Wednesday morning Airtel Africa confirmed that its mobile-money arm, Airtel Money, intends to float in London at a valuation of $8bn to $9bn, which would make it the City's largest new listing since 2021.

The FTSE 100

Monday was the week's only session with real direction. With crude sliding from $104.37 on Friday to around $100.28, the index recovered roughly half of Friday's sharp fall, and the day's leadership was a study in what cheaper oil does to London. Spirax rose 280.0p to 7,185.0p and Rolls-Royce added 54.8p to close at 1,504.8p, up 3.78% — in sterling terms, a little over £15 a share. Marks & Spencer and Burberry were also among the stronger names. The losers were exactly who you would expect: BP fell 15.8p to 542.9p, Shell dropped 50.5p to 3,488.5p, and Glencore and Fresnillo followed the commodity complex lower.

Tuesday reversed the pattern without reversing the mood. Kingfisher was comfortably the best blue-chip performer after raising full-year guidance, closing up around 9%, with Smiths Group not far behind on the back of its own full-year numbers. On the other side, BAE Systems fell 57.0p to 1,993.0p, and London Stock Exchange Group lost 196.0p to 8,154.0p.

Wednesday belonged to energy and defence. BP closed 2.82% higher and Shell added 1.8% as Brent snapped a five-session losing run; RELX rose 2.16% and Babcock International 1.92%, with BAE Systems and Rolls-Royce also firmer. Banks were mildly supportive, Standard Chartered adding 1.5% and HSBC 1.2%. The heaviest fallers were JD Sports Fashion, down 3.56% on half-year results, Fresnillo, down 2.87% as gold eased under a firmer dollar, and Entain, down 2.77% in its first week outside the index.

That last point matters for the week as a whole. FTSE Russell's September quarterly review took effect at the start of trading on Monday, sending easyJet and Ithaca Energy into the FTSE 100 and pushing Entain and Persimmon down into the FTSE 250.

The FTSE 250 and mid caps

The mid-cap index had the better Monday by some distance, gaining about 1.2% to 24,491.37 as cheaper crude took some immediate pressure off the domestic inflation story and travel, banking and smaller Main Market names responded. It then went quiet: Tuesday closed at 24,507.84 and Wednesday gave back 34.11 points to finish at 24,473.73, leaving the FTSE 250 essentially flat across the final two sessions while the blue chips did the moving.

Entain and Persimmon arrived in the index on Monday from the FTSE 100. Entain's demotion follows a share price down roughly 30% since the start of the year and about 42% over twelve months, with the increase in UK remote gaming duty from 21% to 40% from 1 April 2026 a large part of the reason — the company absorbed a £56m hit to underlying first-half EBITDA from the higher rate alone.

AIM provided the week's sharpest moves in both directions. Craneware, the Edinburgh-based healthcare software group, was the standout casualty on Monday. At the other end, Chapel Down upgraded its profit expectations on Wednesday and Pollen Street Group, on the Main Market, jumped on confirmation of take-private talks. M&C Saatchi fell after interim results on Tuesday. The FTSE AIM All-Share itself barely moved across the midweek sessions.

The week's biggest movers

Craneware (CRW.L) was the week's worst. The AIM-quoted group, whose customers are US hospitals, clinics and pharmacies, took a cautious view of revenue for the year to June 2027 and now expects it to land around its annual recurring revenue of roughly $185m. The reset follows delays to the US 340B drug discount programme and a cyber incident, disclosed in July, involving unauthorised access to part of its data environment and the exfiltration of data. Shares fell about 25% to roughly 1,006p, with Peel Hunt cutting forecasts.

Pollen Street (POLN.L) went the other way on Wednesday, rising as much as 16.6% to 950p, its highest since January, after confirming it had begun a strategic review and was in talks over a possible take-private. The firm manages £8.4bn across private equity and private credit and counts Shawbrook and Bunq among its holdings. It stressed the talks are early-stage with no certainty of an offer.

Chapel Down (CDGP.L) rose about 9% to 50p after telling the market that 2026 adjusted EBITDA should beat the £3.7m consensus by at least 10%, helped by a shift towards higher-margin traditional-method sparkling wine.

M&C Saatchi (SAA.L) fell about 6% to 138p on Tuesday. The advertising group swung to a statutory pre-tax loss of £161,000 from a £4.3m profit, after £3.7m of restructuring and acquisition costs, and its house broker trimmed its price target, citing the continuing conflict in the Middle East weighing on the group's operations there.

Company news in focus

The Airtel Money listing is the standout. The business, owned by FTSE 100 constituent Airtel Africa (AAF.L), is targeting around $800m of proceeds at an $8bn to $9bn valuation, with a free float of at least 10%. It processed $213bn in the twelve months to June across roughly 53 million monthly active users, and reported revenue of $1.346bn and EBITDA of $676m for the year to March 2026 — the company reports in dollars, so those are dollar figures, not sterling. The offer comprises existing shares only, so it raises no new capital. A prospectus is expected in early October.

easyJet (EZJ.L) returned to the FTSE 100 on Monday, six months after relegation, though its stay may be short: the airline agreed a £5.7bn takeover by Apollo Global Management in August at £7.15 a share. Ithaca Energy (ITH.L) joined alongside it after a run that has lifted the shares roughly 64% so far this year.

AstraZeneca (AZN.L) said on Wednesday that its Trixeo Aerosphere candidate had been approved in the European Union as a maintenance treatment for asthma in patients aged 12 and over.

Balfour Beatty (BBY.L) said on Wednesday it plans to add 2,000 UK staff over the next two years as it scales up for infrastructure demand — a rare piece of unambiguous hiring news in a week otherwise dominated by cost pressure.

Earnings and trading updates

Kingfisher's half-year numbers on Tuesday were the pick of the week. Adjusted pre-tax profit rose 9.9% to £404m for the six months to 31 July, and the group lifted full-year adjusted pre-tax profit guidance to £595m-£635m from £565m-£625m, with free cash flow guidance raised to £480m-£520m. The split beneath was stark: like-for-like sales grew 5.6% at Screwfix but fell 2.9% at B&Q, leaving UK and Ireland like-for-likes up just 0.4%.

Smiths Group reported full-year results the same morning. Organic revenue rose 1.2% to £1,937m and headline operating profit 1.9% to £399m, for a 20.6% margin, with continuing earnings per share up 6% to 86.8p. The larger story was portfolio: the completed £3.3bn sale of the Detection and Interconnect divisions swung the group from £462m of net debt to £1,747m of net cash. Management guided to around 4% organic revenue growth in the year to July 2027.

JD Sports Fashion delivered the week's most difficult set on Wednesday. Organic sales for the first half of its 2027 financial year fell 0.7% to £5.90bn from £5.94bn, and profit before tax and adjusting items dropped to £282m from £351m. North America, its largest region at 38% of sales, was the weak spot with like-for-likes down 4.0%. The company pointed to soft consumer demand, higher youth unemployment and a highly promotional market.

Renishaw was the quieter success. The precision engineering group posted record full-year revenue, up 14% to £815.8m, adjusted pre-tax profit of £168m and adjusted earnings per share of 179.5p, up 30%. It proposed a 65.2p final dividend plus a 70.0p special interim dividend, and the shares rose 2.7% to 5,685p.

Macro and the Bank of England

The Bank of England left Bank Rate at 3.75% at its September meeting, but the vote was the interesting part: 6-3, with Huw Pill, Catherine Mann and Megan Greene all voting for a quarter-point increase to 4%. The Committee also agreed unanimously to run its gilt holdings down to zero over a multi-year plan, at an average £46bn a year to 2034, including £20bn of annual sales. August CPI was 3.1%.

Two data points landed inside this week's window. Tuesday's public finances showed August net borrowing of £18.268bn, above the £15.5bn economists expected and around £3.5bn more than the OBR had forecast, with net debt at £2.9855tn, or 93.8% of GDP — uncomfortable numbers ahead of the 28 October Budget. Wednesday's flash PMIs then showed the composite index easing to 51.7 from 52.5, with services at 51.7 and manufacturing firmer at 52.0, a combination S&P Global reads as consistent with quarterly growth of about 0.1%.

Gilts held broadly steady, the ten-year yield sitting around 5.23% and the two-year at 4.66% on Wednesday, with markets still pricing a meaningful chance of a November increase. Sterling was the clearer casualty, falling 0.88% to about $1.3228 on Wednesday, its weakest since late June, as the dollar firmed on hawkish Federal Reserve commentary and the US ten-year Treasury yield touched 5.1%, a nineteen-year high.

Still to come

Vistry's half-year update is the one most directly tied to this week's themes: the housebuilder carries a forward order book of around £4.5bn, but its open-market business is still working against consumer affordability and a rate path that has moved against it.

This article is for information and education only. It is not financial advice or a recommendation to buy, sell or hold any investment. Always do your own research.