Finding the best shares to buy is a challenging feat. But for the intelligent investors who spot the under-the-radar winning opportunities, some impressive long-term returns can emerge, even among boring large-cap companies.
In fact, with enough time and compounding, even FTSE 100 stocks can eventually grow a modest portfolio to millionaire territory.
So, how can investors actually find these top-notch stocks? And which companies are the experts backing on their wealth-building journeys?
The best UK shares use short-term challenges
At some point along its journey, a business will encounter enormous disruptions or challenges.
But it’s the businesses with the financial resources, superior cash flows, and competitive advantages that are often the ones that make it through the storm.
The strongest of these are those that leverage short-term chaos to steal market share from their weaker rivals. That way, when the wider industry or market cycle starts to recover, the business will be in a much stronger position to dominate and reward shareholders with chunky long-term returns.
So, the question now becomes, which UK companies are currently trying to do just that?
Spoilt for choice
In 2026, there is a long list of companies investing through the short-term downturn in the pursuit of long-term gains.
Barratt Redrow is consolidating smaller homebuilders in a falling housing cycle. Greggs is building out new factory facilities to support an expanding network of retail stores during a consumer spending slowdown. And BT Group is revamping its telecommunications infrastructure to bring down operating costs in an inflationary environment.
But one FTSE company that currently stands out as potentially one of the best shares to consider buying now is Marks & Spencer (LSE:MKS).
Under the new leadership of Stuart Machin since 2022, the company has significantly changed its destiny, expanding its food business ahead of the industry while simultaneously capturing previously lost ground within the fashion sector. In fact, during 2025, Marks & Spencer achieved its highest market share in womenswear in nine years.
This operational momentum has already delivered a 130%+ increase in the stock’s market cap over the last five years, or around 19% on an average annualised basis.
However, with the forward price-to-earnings ratio standing at just 10.5, some institutional analysts think more momentum could still lie ahead.
For example, the team at UBS recently issued a 425p share price target – roughly 16% ahead of current levels. And if M&S continues to outpace its industry in the long run, the stock could turn into a quality compounder that eventually helps elevate a portfolio to seven-figure territory.
What’s the verdict
While M&S shows promise, it’s important to recognise it’s not a risk-free investment. As a more premium food retailer, the company can be sensitive to economic shocks as consumers seek better value for money from fiercely competitive discounters.
There’s also understandable concern about the firm’s ability to protect its upgraded technological infrastructure. After all, its cybersecurity systems failed to protect the firm from a ransomware attack last year. And while the business has seemingly bounced back, another breach could signal a more structural vulnerability.
Nevertheless, for investors looking for potential top-notch shares to buy that are hiding in plain sight, Marks & Spencer could be worth a closer look.
