The UK stock market’s most consistent winners and losers revealed

Investors naturally want shares to deliver year after year, but the stock market rarely moves in a straight line.

The perfect FTSE 350 share would be one which has delivered a positive total return (share price gain plus dividends) in every year of the last decade with consistency and low variability.

Dividends have historically provided a significant component of the returns from UK companies, so excluding them would disadvantage mature income paying companies from our search.

A useful way to measure variability is to look at how a company’s annual total return fluctuates around its average. This statistical measure is called standard deviation and sometimes referred to as volatility.

The lower the better, because it gives an investor a ‘smoother’ journey with fewer bumps in the road.

Even exceptional long-term investments suffer from periods of underperformance. Outstanding investments can lag when a sector falls from favour, its valuation contracts or another corner of the market enjoys a temporary boom.

After crunching the numbers for companies with a market value of more than £400 million, it will not be surprising to learn there aren’t any companies which have delivered a positive return in every one of the last 10 years, particularly given this period encompasses the Covid pandemic.

We have narrowed the universe down by restricting the list to companies which have delivered a positive return in at least eight of the last 10 years, which have also shown the least amount of variability. Past returns offer no guide to the future, but consistency of performance is still a useful thing to track.

Companies with the most consistent positive annual returns

The table is sorted by consistency of returns which is calculated by dividing the annualised total return by standard deviation. This provides a type of risk adjusted return or consistency score with higher values being better than lower ones.

For example, construction company Galliford Try has delivered an exceptional 10-year annualised return of 50.3% a year and standard deviation of 46.9%, equating to a consistency score of 1.07 (50.3/46.9).

Galliford Try’s fortunes changed significantly in 2020 when it sold Linden Homes and the Partnerships and Regeneration business to Bovis (now Vistry), leaving it with a simplified group structure.

For the financial year to June 2026 Galliford Try reported £259 million of cash, no pension liabilities and an undrawn credit facility which gives the firm the financial strength and resiliency to be able to invest, acquire businesses and return surplus cash to shareholders.

The company increased its 2026 dividend by 24% and announced a new £15 million share buyback alongside continued investments and acquisitions.

A consistent performer

Diploma delivered a 22.6% annualised 10-year total return, with 25.2% annual volatility, giving a consistency score of 0.9 and a positive return in eight years over the last decade.

For comparison, the FTSE 350 index has delivered a 10-year total return of 8.4% with an annual volatility of 11.9%, equating to a consistency score of 0.7, and the same eight out of 10 years of positive returns.

Halma’s consistency reflects pricing power which comes from selling specialised mission critical components or consumables that represent a small part of a customer’s total cost.

Exposure to areas including aerospace, defence, data centres, energy, infrastructure and diagnostics provided structural growth without relying on a single end market.

Which are the least consistent performers?

Broadcaster ITV and advertising group WPP have shown inconsistent performance and volatile share price performance over the last decade, reflecting disruption to their businesses from new competitors in the digital sphere.

This has resulted in weak growth and recurring strategic resets as the companies spend to build their digital presence. Linear television has been losing audiences to digital and streaming platforms, which has weakened the attraction of traditional tv advertising, denting ITV’s core profit engine.

The market has struggled to value ITV’s declining but cash generative broadcasting business alongside its growing digital platform and global production capabilities.

That conundrum will potentially be solved by ITV’s recent decision to sell Media and Entertainment to Sky, leaving the company as a standalone content business, while some of the proceeds are expected to be returned to shareholders.

WPP has been affected by the likes of Google and Facebook cutting out the middleman and selling advertising directly to brands. Under former Microsoft UK boss Cindy Rose, appointed in late 2025, the company is pursuing its latest turnaround attempt.

Saga has set a new course

Over-50s specialist travel outfit Saga has been one of the weakest performers and most volatile shares in the FTSE 350 over the last decade, reflecting excessive debts and the impact from the pandemic.

Over the last three years the shares are up six-fold as investors have warmed to the company’s turnaround plan, which involved partnering with insurer Ageas, cutting indebtedness and getting back to its roots with a focus on the tourism sector.

At the half year to July the company reported net debt had fallen to £429 million, representing a more manageable two times EBITDA (earnings before interest, tax, depreciation, and amortisation).

Underlying pre-tax profit almost doubled to £46.6 million and operating cash flow improved by nearly a third to £101 million.

What conclusions can we draw from the analysis?

It is important to distinguish share price consistency from business consistency.

Investors should look for businesses which possess recurring revenues, pricing power, strong free cash flow, manageable debt, attractive returns on capital and management with a record of sensible reinvestment.

But even companies possessing these characteristics will not necessarily beat an index every calendar year. It is worth reflecting on whether the investment case has deteriorated or whether the share is temporarily out of fashion.