New analysis suggests Scotland's 48p top rate of income tax may have reduced public revenues by around £22million in its first year, after higher earners altered their financial affairs to avoid the higher rate.
Dan Neidle, founder of Tax Policy Associates and a former member of the Scottish Government's Tax Advisory Group, said the evidence suggests Scotland has "fallen over the Laffer curve" – the point at which higher tax rates begin to reduce, rather than increase, tax receipts.
According to the analysis, the 48p rate on earnings above £125,140 may have reduced revenues by between £15million and £30million, with Neidle estimating the most likely figure at £22million.
"We can't be sure, but the evidence we have is consistent with the 48p rate losing about £22 million of tax revenue for Scotland," Neidle said.
"I hope the Scottish Government takes a very careful look at the evidence and decides whether, politics aside, it's in Scotland's interest to keep the 48p rate."
The Scottish Government disputed the findings, highlighting Scotland's economic performance and arguing its progressive tax system funds policies including free university tuition, free prescriptions and the Scottish Child Payment.