Reform arguments usually run on theory; this one runs on a number. Before it was suspended, Zambia’s TAZAMA open-access fuel framework cut import premiums by roughly 50%. That single figure does more work than any model, because it is not a projection — it is an outcome the country has already recorded and then switched off. Most policy debates trade in what might happen; this one starts from what already did.

The mechanism behind the minus-50% is the plainest in economics. An import premium is the margin stacked on top of the global fuel price to cover the cost and rent of bringing product into a landlocked market. Channel that supply through a single route and the margin is whatever the controller can charge. Open the pipeline to competing importers and the margin compresses, because each player now has to price against the next. The IMF staff report cites the halving as a clean illustration of a general rule: competition lowers supply costs, and it does so faster than regulation can.

The broader read, set out in the IMF concluding statement, is that open access is not an ideological preference but a measured cost cut with the evidence attached. For a fuel-import economy where pump prices feed transport, food and the wider cost base, a 50% lighter premium is a structural saving, not a marginal one — it loosens the whole cost chain rather than trimming one line of it. The case for liberalising supply chains rarely comes this well documented. Zambia ran the experiment, banked the result, and now has the receipt to justify running it again.