Gross to net

Between the two sit mandatory rebates, confidential discounts agreed with national payers, clawbacks triggered when a health budget is breached, and paybacks when real world volumes exceed the forecast the price was agreed against. None of them appear on the list.

In Europe the confidentiality is deliberate. If a discount agreed in one market became visible, the next payer would open its negotiation from that number, so companies pay for opacity by accepting confidential terms. The practical result is that a published price is weak evidence about realised revenue.

The gap is not stable either. It generally widens across a product's life as more national agreements are struck, as volume thresholds are crossed and as competitors arrive. A gross to net ratio taken from the launch year and held flat across a ten year forecast is optimistic by construction.

This is the European counterpart to the American rebate problem, where pharmacy benefit managers extract discounts off a manufacturer set list price. The mechanism differs, the direction of the error does not: forecasting on list overstates revenue in both systems.