How will the block grant be adjusted to account for tax devolution?

Following devolution of around £2.5 billion tax revenues by 2019, the Welsh Block grant will be cut by a corresponding amount.  Looking forward, how the block grant is adjusted will change each year depending on changes to equivalent tax revenues in England and Northern Ireland.  So the relative performance of Welsh tax revenues will have a direct impact on how much the Welsh Government can spend in the budget.  The block grant adjustment model is set out in the fiscal framework for Wales​.