Keith Cochrane, chief executive of the Weir Group, also refused to rule out the relocation of the firm's Glasgow headquarters if Scotland leaves the union.
Mr Cochrane was addressing a conference on Scotland's future hosted by the Institute of Chartered Accountants Scotland in Edinburgh.
He said: "Until the independence negotiations, we won't know what the outlook will be and what it will mean for businesses.
"What I do know is that it will create a substantial hiatus in future investment."
Mr Cochrane added: "I know Weir would be very cautious in committing to new projects until we are certain of the answers to some basic questions like what currency arrangements an independent Scotland will have.
"That is not a statement I make lightly, but I am certain I will not be alone."
He continued: "And even after negotiations are settled, foreign investors may be wary of committing to Scotland for a couple of years as they wait to see how the newly independent economy performs."
Mr Cochrane said his firm's choice to be headquartered in Glasgow meant that its Scottish operations run at a loss which is offset by profits made elsewhere.
"At the moment, we have the option to offset losses in one part of the UK with the profits we make in other parts.
"It's a system called group relief and I am sure it will be familiar to many of my fellow chartered accountants in this room. But group relief couldn't survive independence because the current UK tax arrangements would no longer exist.
"At Weir, we estimate in 2013, the changes to corporation tax suggested by the Scottish Government would have saved us approximately £400,000 but the flexibility offered by UK group relief is worth almost nine times that figure - demonstrating why the tax system should be looked at in the round."
Asked if Weir would remain headquartered in Scotland following a Yes vote, Mr Cochrane said: "I cannot give you an answer to that question. The honest answer is I don't know."
The conference also heard from Jim McColl of Clyde Blowers, who supports a Yes vote.
Asked if he would consider moving back to Scotland if the country becomes independent, he said he would not want to give up his home in Monaco.
But he added: "I would consider coming back as a domicile."