Telecom · April 2026 · 9 min read
Stress-testing a national fibre tariff against FX and inflation
A wholesale fibre tariff is a twenty-year commitment. Base-case clearance is table stakes. What determines whether the network becomes an infrastructure asset or a stranded one is how the tariff behaves at the P20 downside of the three risks every African broadband programme actually faces.
The argument
Those three risks are consistent across the continent: local-currency devaluation against dollar-denominated construction and refinancing debt, construction inflation running well above CPI, and regulatory-approval delay on tariff resets running many quarters on the historical record. A tariff that does not carry an explicit indexation formula, a delay-adjusted reset clause, and a first-loss tranche sized to the downside shortfall is not a wholesale model — it is a hope.
What we see in the field
On an illustrative East African programme, the base-case tariff comfortably clears required DSCR. Under a downside joint stress across FX, construction inflation and reset delay, coverage falls below breakeven. Rebuilt with an indexation formula and a first-loss concessional tranche sized to the downside gap, coverage clears comfortably under the same stress. That is typically the version regulators adopt and DFIs close against.
What it changes
For regulators, publishing a tariff without a stated stress-test scenario is a policy choice with a fiscal cost. For sponsors, the tariff conversation has moved from cost-of-service to distribution-of-service.
Where to start
Before the next open-access tariff is published, run it at P20 across FX, construction inflation and reset delay. If the DSCR does not clear, redesign the indexation or the capital stack — not the marketing.
