An open letter to the Scottish people from 120 business leaders is calling on them to back the union to ensure Scotland's economy continues growing.
Organised by Weir Group chief executive Keith Cochrane, the letter warns that the case for independence has not been successfully made and the uncertainty caused by the debate is worrying business, which could in turn deter investment.
The letter, quote by Sky News, said: 'As job creators, we have looked carefully at the arguments made by both sides of the debate.
'Our conclusion is that the business case for independence has not been made. 'Uncertainty surrounds a number of vital issues including currency, regulation, tax, pensions, EU membership and support for our exports around the world - and uncertainty is bad for business.'
The letter was also signed by HSBC chairman Douglas Flint, Thales' Victor Chavez and Ian Curle of The Edrington Group, which produces Famous Grouse whiskey.
The business leaders, who signed in a personal capacity, warned of the wider economic risks.
'Our economic ties inside the United Kingdom are very close and support almost one million Scottish jobs. The rest of the UK is Scotland's biggest market by far,' the letter said.
'Today Scotland's economy is growing. We are attracting record investment and the employment rate is high.
'We should be proud that Scotland is a great place to build businesses and create jobs - success that has been achieved as an integral part of the UK.
'The UK gives business the strong platform we must have to invest in jobs and industry. By all continuing to work together, we can keep Scotland flourishing.'