Jason Levien, who heads up the consortium with fellow American Steve Kaplan, revealed the figure at Swansea's Liberty Stadium on Friday.
Levien, though, would not go into financial specifics about the arrangement.
The reported £110million deal, which received Premier League ratification on July 1, was completed on Thursday night after a press conference to announce the purchase earlier in the day had been postponed because of a dispute between two minority shareholders.
"I think we've bought into a club with an exciting history and a tremendous fan-base, and we are thrilled to have the opportunity to be a part of it," Levien, who was accompanied by Swansea chairman Huw Jenkins, told reporters.
"We are taking a controlling interest in the club
I believe, ultimately, about 68 per cent of the club is what we will be purchasing.
"We think it is a very valuable club, and one that are we are deeply appreciative to be a part of, but I am not going to go into specific numbers on the investment.
"I first spoke to Huw about a year ago
We had conversations about football, the philosophy of football and how the club is run here.
"I first came to visit late last summer
I thought it was a unique opportunity
The Premier League is a unique opportunity, but above that, we think Swansea is a terrific fit for Steve and I to be a part of."
Source : PA
Source: PA