Spread Too Thin: The Strategic Cost of Adjacency Expansion in British Corporate Groups

The language of diversification has always carried a reassuring quality. To spread risk across sectors, to build a portfolio that does not depend on any single market's fortunes, to extend into adjacent territories where existing capabilities can be redeployed — these are presented, almost universally, as marks of strategic maturity. For British corporate groups operating across multiple verticals, the diversified portfolio has become something close to an article of faith.

It is worth asking, with some seriousness, whether that faith is warranted.

The argument for diversification is not without merit. Concentrated exposure to a single sector carries genuine risks, as the businesses that lived through the financial crisis of 2008 or the structural disruption of retail over the past decade can readily attest. A portfolio with genuine breadth can, in principle, absorb sector-specific shocks without catastrophic consequence. The theory is coherent.

The practice, however, is considerably more complicated — and considerably less flattering to the diversified model.

The Adjacency Assumption

Most corporate expansion into new sectors is justified on the basis of adjacency: the belief that proximity to an existing market means that the group's capabilities, relationships, and institutional knowledge will transfer with sufficient fidelity to constitute a competitive advantage in the new territory.

This assumption is made far more frequently than it is tested. Adjacency in a strategic sense — genuine overlap in customer need, operational capability, or technological competence — is a narrower concept than it appears when drawn on a slide. Two sectors may look adjacent on a market map while being separated, in practice, by entirely different customer buying behaviours, regulatory environments, talent pools, and competitive dynamics. A group that excels in facilities management, for instance, may find that expansion into construction services brings it into contact with a procurement culture, a risk profile, and a margin structure that bears little resemblance to what it knows.

The adjacency assumption is further complicated by the speed at which it is typically made. Acquisition timelines are compressed by competition for assets. Due diligence, however thorough in financial terms, rarely provides a granular picture of how well the acquiring group's operating model will translate into the target's market. By the time the integration is complete and the reality of the new sector becomes apparent, the capital has been deployed and the strategic commitment has been made.

What Breadth Actually Costs

The costs of poorly conceived diversification are rarely visible as a line item. They manifest instead in the texture of the business: in management attention that is perpetually divided, in capital allocation decisions that are made on the basis of political balance rather than genuine return potential, and in the gradual erosion of the deep sector expertise that originally gave the group its edge.

Management attention is perhaps the most underappreciated resource in a corporate group. Senior leadership time is finite. When that time is distributed across five or six sectors, each with its own competitive dynamics, its own regulatory pressures, and its own operational challenges, the depth of engagement that any single business receives is necessarily limited. The group's most capable leaders are asked to be generalists when the market increasingly rewards specialism.

Capital allocation presents a related problem. In a diversified portfolio, the temptation to distribute investment across the group — to give each business unit a proportionate share of available resource — is strong. It is politically expedient, and it avoids the difficult conversations that come with concentrating capital in the businesses that have the clearest right to win. But proportionate distribution is not strategic allocation. It produces a collection of adequately resourced businesses rather than a smaller number of genuinely well-capitalised ones.

The consequence, across Britain's mid-market, is a familiar pattern: groups that hold credible positions in several sectors without dominant positions in any of them. Competent, but not compelling. Present, but not leading.

The Resilience Myth

Proponents of broad diversification frequently invoke resilience as its defining virtue. A portfolio spread across multiple sectors, the argument runs, is insulated against the failure of any individual market. When one business struggles, others compensate.

This is true, as far as it goes. But resilience and competitive strength are not the same thing, and optimising for one at the expense of the other is a trade-off that deserves explicit acknowledgement rather than silent acceptance.

A corporate group that is resilient because it is never sufficiently exposed to any single market to be significantly harmed by it is also never sufficiently committed to any single market to be genuinely formidable within it. The protection that diversification provides against downside risk is purchased, in part, by capping the upside that comes from genuine market leadership.

There is also a question of what kind of resilience is actually being sought. For groups with patient capital and long investment horizons, portfolio breadth can provide genuine protection. For groups operating in competitive markets where capital efficiency and return on invested capital are scrutinised by external stakeholders, the resilience argument can become a convenient cover for the absence of a sharper strategic thesis.

A More Demanding Standard

The alternative to reflexive diversification is not concentration for its own sake. It is a more demanding standard for what constitutes genuine strategic adjacency, applied with more rigour than the concept typically receives.

Before committing to expansion into a new sector or geography, a corporate group should be able to answer, with specificity, three questions. First: what is the precise capability or asset that the group brings to this market that a well-capitalised incumbent does not already possess? Second: what is the realistic timeline to a position of genuine competitive strength, and what will it cost in management attention and capital to get there? Third: what is the opportunity cost — what will the group not be doing with those resources if it commits them here?

These are not comfortable questions. They tend to produce fewer expansion decisions than boards accustomed to growth narratives would prefer. But they are the questions that distinguish strategic diversification from the accumulation of exposure — and for British corporate groups that have spent years spreading themselves across adjacent markets without achieving dominance in any of them, they are overdue.