They said since Scottish income tax was introduced in 2017-18, net migration of working age people from the rest of the UK to Scotland has averaged almost 7,000 per year.
"Scots enjoy a range of support not available in England such as free tuition - ensuring access to university based on the ability to learn and not the ability to pay."
Stupart said the income tax differential between Scotland and England was also creating issues within firms operating cross-border.
From April, earners of £75,000 or more will pay the advanced rate of 45 per cent, while the highest earners will pay 48 per cent versus 45 per cent in England.
The Scottish Fiscal Commission has estimated introducing the 45p rate band and raising the top rate will increase income tax revenue by £82mn. Once the freeze in the higher rate threshold is factored in, the government estimates it will have £389mn more to spend.
But for taxpayers, Stupart said, this meant someone on a salary of £50,000 will pay £1,500 more in income tax in Scotland than they would in England. For a salary of £85,000 the gap is even more pronounced at close to £2,600.
"The most unhelpful thing for the sector is the differences in tax regimes across the different countries," he said.
This was particularly true where advice firms operate cross-border and have employees in both jurisdictions, something becoming more common with increased consolidation, he said.
"How do you sit there and talk to an employee in Leeds and an employee in Edinburgh who have to buy homes which probably cost the same thing, you're trying to pay them roughly the same amount but one comes out net of tax less than the other.
"That has to have motivational issues for the workforce."
Businesses might choose to pay a higher gross salary in Scotland, he added, but this comes at a cost to the business.
Stupart said: "The income tax rate differential escalating as it will from April, I think that just seeks to exasperate the risk of that entrepreneurial talent looking to across the border, thinking well what ties do I have to Scotland, what am I benefitting from elsewhere."
But the government spokesperson said the 2023 EY Attractiveness Survey showed the number of FDI projects in Scotland in 2022 had increased by 3 per cent to a record high of 126. This compared with growth of 1 per cent across Europe and a fall of 6 per cent in the UK.
"Scotland continues to be attractive to businesses, with foreign investment growing faster than the UK’s and Europe’s in recent years," they said.
