Senior figures in the Scottish financial services industry have clashed over how independence would affect business.
Industry body Scottish Financial Enterprise (SFE) said higher costs and complexity would hamper competitiveness following independence.
A briefing paper also insisted a new financial regulator would be required.
But a group including the former chief executive of RBS has said independence could lead to more jobs and investment.
The clash came ahead of the Scottish independence referendum, on 18 September.
The financial services industry employs about 100,000 people in Scotland directly, and another 100,000 indirectly.
In its briefing paper on Scottish independence, SFE said there were "some major risks and uncertainties" around independence, including the nature and cost of any new regulatory framework and the "likely" separation, over time, of the Scottish and UK financial services markets.
The paper said international competitiveness was likely to be affected as Scottish-based firms would have to deal with extra costs and complexities that would not apply to competitors.
Jobs and investment
The body also insisted there were strong reasons to believe negotiations on independence would last a lot longer than the 18 months anticipated by the Scottish government.
And it recommended that work should be done to prepare for a new and separate currency should Scotland vote "Yes" in referendum, adding that it expected Scotland to become a member of the European Union.
SFE, which describes itself as "politically neutral", insisted the paper was a briefing for its members rather than a formal position adopted by its board.
It states: "Many of the most important questions about the consequences of a 'Yes' vote cannot be answered before it occurs. Uncertainty is extensive and likely to continue for some time after such a vote.
"Compared with the business environment as it stands, greater cost and complexity are certain. The industry will have to reconfigure to deal with the changed political landscape."
In response, a group of financial services figures led by Sir George Mathewson said there were "significant opportunities in an independent Scotland".
In a letter to the Financial Times newspaper, Sir George, the former chairman and chief executive of RBS, said there were "certainly opportunities to attract more jobs and investment to Scotland".
The letter, which was signed by business figures including former SFE executive director James Scott, fund manager Angus Tulloch, and Prof David Simpson, a former advisor to Standard Life, insisted that staying in the Union presented uncertainty around taxes, regulation and whether the UK would remain a part of the EU.
It stated: "Any truly objective analysis of what the referendum means for business requires a more thoughtful consideration of the UK's current trajectory."
Martin Gilbert, chief executive of global investment group Aberdeen Asset Management, said of the SFE briefing: "Our position is neutral.
"It's unfortunate that the document really just outlines all the negatives rather than being balanced ... it's unfortunate that it hasn't come from the board of SFE."
Scottish Finance Secretary John Swinney said it was clear the independence debate attracted diverse views from across the financial services sector.
He added: "SFE set out many similar arguments ahead of devolution about taxation and uncertainty which have been shown to be misplaced, but in any event this is simply a briefing note from SFE officials, and not the view of the industry or of organisations within it.
"The reality is that Scotland is a wealthy country, with a successful financial services industry which is more than capable of thriving under any constitutional position - a position recently recognised by the chief executive of SFE."
However, Alistair Darling, the former chancellor and leader of the pro-Union Better Together campaign, said independence would put jobs at risk.
"This is another serious report from impartial experts which makes the case that Scotland is better being part of the UK and the UK is better with Scotland at its heart," he added.
"The financial services industry is vital to Scotland's economy, particularly in Glasgow and Edinburgh.
"Being part of the larger UK is vital in sustaining these jobs and generating the money to pay for schools and hospitals, pensions and benefits. It's clear that independence would put this at risk and cost jobs in Scotland."