A Scotland-based company which employs 3,500 people around the world has threatened to move its headquarters elsewhere if independence is voted for.
Alan Savage, chairman of the the Orion Group, said he would personally live in an independent Scotland but the “uncertainty” over currency, trade, tax and EU membership may involve “running the business from somewhere else”.
The Inverness-based recruitment boss is a former chairman of Inverness Caledonian Thistle football club, and donor to the pro-UK Better Together campaign.
Meanwhile, the SNP has hailed comment from a distinguished US publishing house welcoming the prospect of Scottish independence.
Slate, an economics website run by former Washington Post owners Graham Holdings, said “small countries are generally a lot better run than the bigger ones”.
In an article for the Huffington Post, circulated by Better Together, Mr Savage said: “Uncertainty is a nightmare for anyone running a business today.
“My company, run out of Scotland with 1,500 workers across the UK and 3,500 globally, needs economic and political stability to keep it healthy and allow us to continue to invest in a world-class workforce.
“We need certainty on a wide range of business-crucial areas, including embassies, trade, tax, and membership of the EU. Being part of the UK has given Scottish-headquartered companies like Orion certainty on these issues.
“The Scottish Government’s White Paper wish list for independence doesn’t give business any assurances on these ‘must dos’.
“But for me the biggest uncertainty of all in Mr Salmond’s separation experiment is on the vitally important issue of currency.
“However, Alex Salmond’s point blank refusal to set out a currency plan B, as well as his reckless threat to default on our debt if he doesn’t get his eurozone-style currency union, means that I have to come up with a plan B of my own.
“This would involve still living in Scotland, but running the business from somewhere else.”
In an article circulated by the SNP, Slate business and economics correspondent Matthew Yglesias said: “Scotland’s independence referendum later this year hasn’t gotten much coverage in the United States and most of the coverage I have seen has largely reflected the international community’s knee-jerk hostility to the redrawing of borders.
“But I have to say that my priors go in the other direction, and I’m favourably disposed.
“The main reason is that it seems to me that in the European context where everyone is a stable democracy with a mixed-market economy, the small countries like Netherlands, Denmark, Finland, etc are generally a lot better run than the bigger ones.
“For one thing, smaller countries have simpler institutional arrangements since you’re not trying to accommodate size by embedding complicated federalism mechanisms into the already complicated framework of the European Union.
“But for another thing, I think the debate over welfare state design gets more sensible when you’re talking about a small jurisdiction. A place like Scotland is a sufficiently small share of the United Kingdom that it makes sense for a Scottish political activist to be more focused on ‘how much money does this program bring to Scotland?’ than on ‘how good is this program at generating social benefits in a cost-effective way?’
“An independent Scotland, like an independent Wallonia or other possible new European mini-states, would have politics that I think would ultimately be more constructive.”
The SNP said the Huffington Post article is a rehash of claims Mr Savage made several months ago in the national press.
A spokesman said: “An independent Scotland will keep the pound, and will offer huge opportunities for business - as underlined by the more than 1,300 business people who have joined the pro-independence Business for Scotland group.
“And the only uncertainty facing Scottish businesses is Westminster’s threat to drag Scotland out of the EU against our will, with all the disastrous consequences for jobs, investment and prosperity that would entail.”