When business leaders discuss strategic risk, they usually focus on what is new: the startup investment, cross-border acquisition, digital transformation, or multi-billion-peso capital proposal.
They ask probing questions because the future is unproven. But what about the core business that is already making money?
It has paying customers, steady revenues, a long track record, and a management team that knows how to run it. It supports the broader organization and provides the cash flows on which continued investment depends.
Because it has succeeded for years, we tend to treat the assumptions behind it as facts. That is precisely why it deserves continued examination.
Not every decline is an execution problem. Sometimes management executes brilliantly against assumptions that have quietly expired.
We confuse past success with permanent truth. A successful business model is not an unassailable fact. It is a hypothesis with a long track record.
This is not an argument that mature businesses are inherently vulnerable; many remain highly attractive precisely because their underlying customer needs and economics remain durable.
The Strategic Half-Life
Every business model rests on assumptions: customers will continue to value the proposition, accept the price, buy at a certain frequency, use a particular channel, or support a particular cost structure.
When the strategy succeeds, these assumptions appear validated. But validation is not permanence. Customer behavior evolves. Technology advances. Regulation changes. Competitors find new ways to deliver value. Macroeconomic conditions shift.
This creates Assumption Decay: the company continues executing its operating model effectively while the economic validity of the assumptions underneath it gradually weakens. The discipline is not to assume decay, but to test for it.
I call the period over which a critical assumption retains its economic relevance its Strategic Half-Life.
Different assumptions have different half-lives. A fundamental customer need may remain relevant for decades. A distribution channel may deteriorate in five years. A promotional model may weaken much faster.
The objective is not to predict an exact expiration date. It is to identify which assumptions are decaying fastest and monitor them before deterioration appears in the income statement. Consider mature sectors:
- Retail and FMCG: Brand equity and prime shelf placement may remain valuable even as digital channels weaken traditional customer-acquisition economics.
- Education and professional services: Customers may increasingly question premiums for physical presence when hybrid delivery produces comparable outcomes.
- Luxury and high-end goods: Affluent customers may retain purchasing power while becoming more sensitive to economic friction, social optics, or changing definitions of status.
The important question is: Which assumptions are becoming less economically true?
The Governance Paradox
There is a striking double standard in organizations.
When management presents a new venture, the board asks: What must be true? What could go wrong? What are the triggers for investing more or stopping? But once an asset becomes the core business, those questions may receive less attention.
Familiarity becomes mistaken for certainty.
The board’s role is to provide independent challenge and ask whether the assumptions behind the strategy remain economically valid. One useful question is: “If we were investing in this business today, knowing what we know now, would we build it the same way?”
A “no” does not mean abandoning the core. It means identifying what has changed and deciding whether the business should Defend, Adapt, or Disrupt.
This should not become another reporting exercise or an excuse for the board to second-guess management. Its purpose is to help management make better strategic and capital-allocation decisions while there is still time to act.
From Assumption Decay to Assumption Debt
There is another danger: Assumption Debt.
When an organization operates for years under an assumption, that assumption becomes embedded in its assets, people, incentives, systems, contracts, channels, and culture.
The longer it remains unchallenged, the more expensive change becomes.
This is why strategic adaptation is not simply an innovation problem. It is a capital-allocation and governance problem.
A company can recognize that its business model is weakening and still fail to respond because too much of the organization has been built around yesterday’s logic.
Management owns execution. The board’s role is to ensure that execution remains aligned with the assumptions that underpin the business model.
Three Blind Spots
- The Incentive Trap. The hardest assumptions to challenge can be those closely connected to current performance metrics. When incentives are heavily tied to established revenue or earnings streams, organizations may naturally give greater weight to protecting what is already working.
- Confusing Execution with Expiry. A declining business does not automatically mean poor execution. If execution is the problem, fix execution. If the assumption is expiring, executing the old model harder may only accelerate value destruction.
- Over-Correction. Not every negative indicator means structural decay. A temporary margin decline may reflect a cycle. A permanent shift in customer behavior is different. Organizations must distinguish cyclical noise from structural change before reallocating capital.
Turn Assumptions Into a Decision System
A practical Core Assumption Review should identify the few assumptions that, if wrong, could materially damage the business.
For each critical assumption, management should specify:
- The assumption: What must be true for the model to work?
- The indicator: What observable metric tells us whether it remains true?
- The threshold: At what point does concern become action?
- The response: What will we do if the threshold is breached?
For example, if profitable growth depends on cost of customer acquisition remaining within a certain range, COCA should not merely appear on a dashboard.
The organization should define what level of deterioration would trigger a change in channel strategy, pricing, product economics, or capital allocation.
This turns strategic risk from a discussion into a decision system. More importantly, it gives leaders a way to act before declining performance forces the issue.
The Co-Working Industry Lesson
The co-working industry illustrates what can happen when several assumptions embedded in a business model change at the same time.
Operators built their economics around assumptions about corporate demand, occupancy, pricing, lease duration, and the value of centralized office space. When hybrid work accelerated, some of those assumptions weakened significantly.
The problem was not simply poor execution. In many cases, the underlying economics had changed.
The industry also demonstrated Assumption Debt. Operators that had committed to expensive, long-term leases under the old demand model found it difficult to adjust when customer requirements changed.
The lesson is not simply to “pivot.” It is to ask: Which assets and capabilities retain economic value when the customer’s needs change? Prime locations, IT infrastructure, meeting facilities, and customer relationships may retain value, provided the underlying cost structure and commercial model can be redesigned around new demand.
When an assumption decays, preserve what retains economic value and reallocate capital away from structures that no longer do.
Stress-Test the Core
Every core business is built on assumptions. Every critical assumption has a strategic half-life. At the next strategic review, ask:
- What must remain true for our core business to create economic value over the next three to five years?
- Which assumption has the shortest strategic half-life?
- What leading indicator would tell us it is weakening?
- What threshold would make us change course?
- Are we prepared to Defend, Adapt, or Disrupt before the market makes the decision for us?
The best time to challenge a successful business model is while it is still producing strong cash flows.
Today’s success gives leaders something invaluable: time and capital to adapt.
Use both before the market conducts the stress test for you.
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Josiah Go is chairman of Mansmith and Fielders Inc. He will lead the 2nd Strategy Logic Chain 1-Day Masterclass in Ortigas on October 22, 2026. Email info@mansmith.net for details.