2 undervalued FTSE 100 stocks to consider adding to your portfolio in October

The FTSE 100 has pushed up to all-time highs in 2025, but that doesn’t mean investors can’t find a blue-chip bargain or two.

| More on:

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

Young female analyst working at her desk in the office

Image source: Getty Images

Investors might consider October as a FTSE 100 entry point because history shows it often marks a turning point for stock markets. Despite its reputation for volatility — highlighted by episodes like Black Monday — October frequently acts as a “bear killer,” ending downward trends and kickstarting rallies.

Over the last 20 years, average market returns in October have been positive, typically outperforming September and often supporting gains heading into the winter months. With seasonality pushing returns higher after summer weakness, October could be a opportunity for long-term UK investors seeking to benefit from historical patterns of recovery and market strength.

Melrose Industries

Melrose Industries (LSE:MRO) is a FTSE 100 favourite of mine and certainly one to consider in October. The aerospace and defence group delivered a strong first-half 2025 performance, surprising the market with a 29% rise in adjusted operating profit to £310m.

Building on this, the firm reported that margins expanded to 18% from 14.2% a year earlier, while revenue reached £1.72bn on a like-for-like basis. Engines grew 11% and Structures 3%, showing resilience despite ongoing supply chain and tariff pressures.

The median 12-month target price of 663p suggests more growth potential. But analysts may have been slow to catch up and the valuation looks very attractive.

Management is targeting annual earnings growth above 20% through 2029, yet the stock trades on a forward price-to-earnings (P/E) of just 15.5, with a strong P/E-to-growth ratio under one — in contrast, Rolls-Royce trades at 40 times.

Like Rolls, Melrose has a great economic moat, with 70% of sales coming from sole-source positions. Of course, risks remain, including labour shortages, supply chain bottlenecks, and currency shifts. For investors seeking long-term UK exposure, Melrose deserves attention this October.

London Stock Exchange Group

Analysts’ consensus on London Stock Exchange Group (LSE:LSEG) is unusually strong, with 17 analysts rating the stock a Buy or Outperform (10 Buys, 7 Outperforms) and no Holds or Sells. The average target price of 12,437p is 52% above the current share price, with a range from 11,200p (+37%) to 13,500p (+65%).

On an adjusted basis, EPS forecasts stand at 399p for the year ahead and 442p for 2026. That equates to forward P/E ratios of 20.5 times and 18.5 times respectively. That’s quite compelling given the group’s recurring revenue base, strong margins, and structural growth drivers.

Despite this, the shares have lagged in 2025, reflecting frustration that the company has yet to deliver notable AI-driven product breakthroughs, despite its much-publicised Microsoft tie-up. Investors are looking for evidence that AI integration can materially enhance its data analytics, terminal offerings, and client workflows. That could be on the way.

Risks remain, particularly the threat of market-share erosion to Bloomberg and other rivals, where competition is fierce and sticky client relationships are vital. Also, management needs to deal with platform migration and regulatory compliance, which could bring challenges.

Even so, I think London Stock Exchange Group looks like a high-quality FTSE 100 stock to consider this October. There’s lots to be positive about.

James Fox has positions in London Stock Exchange Group Plc, Melrose Industries Plc, and Rolls-Royce Plc. The Motley Fool UK has recommended Melrose Industries Plc and Rolls-Royce Plc. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Two white male workmen working on site at an oil rig
Investing Articles

As oil prices soar, is it time to buy Shell shares?

Christopher Ruane weighs some pros and cons of adding Shell shares to his ISA -- and explains why the oil…

Read more »

Man hanging in the balance over a log at seaside in Scotland
Investing Articles

How much do you need in an ISA for £6,751 passive income a year in 2046?

Let's say an investor wanted a passive income in 20 years' time. How much cash would need be built up…

Read more »

Smiling black woman showing e-ticket on smartphone to white male attendant at airport
Investing Articles

Why isn’t the IAG share price crashing?

Harvey Jones expected the IAG share price to take an absolute beating during current Middle East hostilities. So why is…

Read more »

piggy bank, searching with binoculars
Growth Shares

1 UK share I’d consider buying and 1 I’d run away from on this market dip

In light of the recent stock market dip, Jon Smith outlines the various potential outcomes for a couple of different…

Read more »

Burst your bubble thumbtack and balloon background
Investing Articles

AI may look like a bubble. But what about Rolls-Royce shares?

Bubble talk has been centred on some AI stocks lately. But Christopher Ruane sees risks to Rolls-Royce shares in the…

Read more »

Black woman using smartphone at home, watching stock charts.
Investing Articles

Will the BAE Systems share price soar 13% by this time next year?

BAE Systems' share price continues to surge as the Middle East crisis worsens. Royston Wild asks if the FTSE 100…

Read more »

Portrait of pensive bearded senior looking on screen of laptop sitting at table with coffee cup.
Investing Articles

Is this a once-in-a-decade chance to bag a 9.9% yield from Taylor Wimpey shares?

Taylor Wimpey shares have been hit by a volatile share price and cuts to the dividend. Harvey Jones holds the…

Read more »

Chalkboard representation of risk versus reward on a pair of scales
Investing Articles

Way up – or way down? This FTSE 250 share could go either way

Can this FTSE 250 share turn its fortunes around? Or has its day passed? Our writer looks at both sides…

Read more »