When firm leaders talk about concentration risk, the conversation almost always lands on clients. Too much revenue from one source. Too much exposure to one sector. Too much dependency on a handful of relationships. All valid. All sensible.
But there’s another concentration risk sitting inside most firms and it rarely makes the risk register.
People.
More specifically: the over-reliance on a few deeply trusted, highly capable individuals who hold together critical workflows, client knowledge and delivery continuity. The people everyone depends on. The people who “just know how things work.” The people you’d clone if HR ever allowed it.
It often feels safe because it’s familiar. These are proven team members. Loyal and experienced. They carry institutional memory, client nuance and process shortcuts built over years. In day-to-day operations, that feels like strength.
Strategically, it’s concentration.
And unlike client concentration, people concentration rarely shows up in dashboards. There’s no neat percentage of revenue tied to one individual. No tidy exposure metric. The risk only becomes visible when something shifts; illness, burnout, resignation, parental leave or even promotion into a role that removes them from delivery.
Suddenly, a surprising amount of the firm’s operational certainty turns out to have been sitting inside one person’s head.
This is where the comparison with client concentration becomes uncomfortable. Losing a large client hurts revenue. Losing a key person can destabilise revenue, delivery, client confidence, and team morale simultaneously. The impact is multi-layered and immediate. Deadlines slip. Queries stall. Knowledge gaps surface. Others stretch to compensate.
And because high-dependency individuals are often the most conscientious, they’re also the most prone to silent overload. They absorb complexity. They rescue timelines. They shield clients from friction. The firm experiences stability precisely because they’re carrying disproportionate weight.
Which makes the risk self-concealing.
Over time, this concentration tends to form in predictable places: long-standing client portfolios managed by one senior, niche technical areas handled by a single specialist or legacy processes that only one person fully understands. None of this is intentional. It’s simply how trust and experience accumulate in firms.
“The challenge isn’t eliminating reliance on talented people — that would be both unrealistic and undesirable. The challenge is distributing operational certainty more evenly so that knowledge, process ownership and delivery capability aren’t sitting in single points of failure.“
This is where many firms start adjusting their resourcing models. Not dramatically. Not disruptively. Just gradually reducing dependency density around individuals. Documenting workflows that were previously tacit. Creating overlap in critical roles. Adding structured support layers so expertise is shared rather than concentrated.
In some cases, that includes selectively extending teams beyond the core office — introducing trained support capacity that can absorb defined components of work under existing leadership. Done thoughtfully, this doesn’t dilute ownership; it reinforces continuity. The key person remains the expert and relationship lead, but delivery resilience increases around them.
Client concentration risk is visible and measured. People concentration risk is quieter — but often closer to the operational heart of the firm. Recognising it isn’t about reducing trust in key individuals. It’s about ensuring the firm’s stability doesn’t rest entirely on their shoulders.
Because resilience, in the end, is simply certainty that continues — even when someone indispensable takes a well-earned holiday.