Uncertainty. The word is inseparable, almost synonymous, with Solvency II. Uncertainty is often discussed in the context of regulatory compliance; it is less frequently mentioned as a barrier to insurers’ day-to-day operations and business as usual planning. Doubts about the start date of Solvency II have all but disappeared now. But clarity on the timeline, and more recently on the Delegated Acts, has given way to a new set of uncertainties. Firms can no longer treat Solvency II as something that will happen ‘sometime in the future’. Concrete decisions have to be taken now. Actual numbers must be filled in forms and budgets allocated. At the same time there are still several requirements, formulas and calibrations that will only be clarified next year, yet others, will be left up to national supervisors. The combination of concrete deadlines and uncertain rules is forcing some firms into a difficult position of having to make long-term future plans based on assumptions and notional principles.