Top share indices including the Dow Jones and S&P 500 would crumble in the event of the US President being forced out of office, said ex-chief executive of General Electric Jack Welch.
It comes as the storm surrounding the US leader shows no sign of abating.
Reports claim the President asked former FBI director James Comey to drop an investigation into Michael Flynn and his connections to Russia.
Mr Welch told CNBC: "An impeachment proceeding would blow the market away."
He added that the firing of Mr Comey was "rookie mistake" and said "you don't make any friends doing it the way [Trump] did it."
Now the President must unite all the different factions in the White House and get back to his message of "Make America Great Again," according to Mr Welch.
It comes as the the US dollar and stocks dramatically dropped during trading on Wednesday.
The Dow Jones and S&P 500 both sank by more than one per cent at the open.
And the dollar was down around 0.4 per cent against the pound and 0.5 per cent against the euro.
Kathleen Brooks, research director at City Index Direct, said: "It’s too early to speculate what will happen to Trump at this stage, however, even Republicans have been talking about subpoenas, and there is certainly the will to get to the bottom of this.
"At best, Trump’s misdemeanours could delay economic policy from coming into action, which could weigh on stocks and the dollar.
"At worst this could lead to impeachment, which would be risk negative in our view and could cause a spike in volatility, which has fallen to rock bottom levels in recent days."