The Welsh Parliament has voted to scrap charitable business rates relief for private schools.
From April, private schools in Wales will no longer be eligible for charitable relief but an exception will be introduced for independent special schools.
Of the 83 independent schools in Wales, 17 receive charitable relief at an annual public cost of around £1.3m or £210 for each of the estimated 6,200 pupils.
Welsh ministers said it would be impossible to “disentangle” the impact from the UK Government’s separate decision to introduce VAT on private school fees.
The Institute for Fiscal Studies estimated the proportion of pupils who may move from private to state-funded schools as a result of the UK changes at three to seven per cent.