The poll of 2400 firms south of the Border by the British Chambers of Commerce (BCC) also shows 63% believe no new business opportunities would be created if Scotland became independent. The same percentage want the allocation of public spending under the Barnett Formula revised in the event of a No vote.
Almost half say that the future currency arrangements are the most important issue, if Scots vote for independence in September. Around one-third back a formal currency union, 28% say an independent Scotland should have its own currency, 18% support adoption of the euro and 8% believe Scotland would be better off using the pound but not as part of a currency union.
Better Together said around one in five Scots jobs was with firms based south of the Border. Ian Murray, Scottish Labour's Shadow Business Minister, said: "Our UK single market means businesses can sell their goods throughout the whole of the UK without any barriers between them and their customers. Why would we want to put that at risk? This survey confirms what some of Scotland's largest employers like Standard Life, RBS and Shell have made clear: breaking up the UK would create huge risks and cost jobs in Scotland."
Murdo Fraser, the Scottish Conservatives' Enterprise Spokesman, said it was now clear that just as the prospect of independence was causing extreme tension among Scottish employers, it was doing the same for most of their counterparts across the UK.
"They don't want to break apart a system that works very well, and these are the people who know best," he said. "A complete lack of clarity from the SNP about a range of factors like currency and regulation is the reason so many people are panicking about the prospect of separation," he added.
But Tony Banks, chairman of pro-independence Business for Scotland, insisted most of the rest of the UK knew independence would benefit Scottish prosperity.
"Scottish independence offers real advantages to everyone, not only in Scotland but across our shared markets in Europe," he said.
"Independence doesn't equal isolation and businesses here are well aware of the opportunities they can gain. Even the Scottish Chambers of Commerce survey issued last week conceded that 53% of its members see the opportunities independence could bring."
He added: "People who run businesses are not fools. They know, as I myself know, that an independent Scotland will give Scotland the brand a far greater opportunity to makes its mark globally and to promote its goods and services across the world."
The SNP's Stewart Hosie said: "Today's survey absolutely underlines the need to vote Yes in September to ensure Scotland can protect its budget and rule out the risk of further Westminster cuts being pushed down on to Scotland once and for all."
The party's Treasury spokesman added: "Businesses elsewhere in the UK know a refusal to share sterling would see businesses south of the Border faced with an extra £500 million in transaction costs. The inescapable truth is a currency union is in the interests of Scotland and the rest of the UK."
BCC Director General John Longworth said: "In the event of a Yes vote, cross-border trading and currency arrangements loom large in businesses' thinking.
"If Scotland votes No, constitutional questions remain around the devolution of power and the distribution of public funding."