The group, led by current Leeds managing director David Haigh and including the MD of the club's sponsors Andrew Flowers, announced their intention to buy a majority share in the club from current owners Gulf Finance House Capital in November.
The consortium had expected the deal to go through in time for funds to be made available for manager Brian McDermott ahead of the January transfer window.
However on Wednesday, Flowers accused GFH Capital of reneging on a deal to sell 75% of their shares to Sports Capital, suggesting that "a number of things have come to light which were not as originally described".
He was also critical of GFH's "11th-hour decision" to open talks with controversial Italian Massimo Cellino, the owner of Serie A club Cagliari.
And now Haigh has released a statement indicating that some of the bidding consortium's backers "ultimately didn't feel able to deliver the financial backing we had hoped was agreed to take the club forward".
Haigh continued: "Despite this, the future of this club remains the most important thing to me personally and I remain totally committed to putting the right team and backing in place to ensure that Leeds United can move forward.
"It is an indication of that commitment that in recent months the Sports Capital consortium and I personally have injected substantial sums into the club to ensure its viability.
"I have met many, many potential investors over the past year and, sadly, while many are keen to talk the talk they have been unable or unwilling to deliver in financial terms. Nevertheless these talks continue with a number of parties to seek the best possible outcome for Leeds United."
He added: "At the same time neither my life nor my job has been made easier by the personal intrusions and abuse directed towards me on social media or by some of the smear campaigns against me personally.
"Equally, some of the speculation & stories published in the media have made things difficult for everyone including the staff, players and supporters."
The club have also released a statement saying: "Following recent media speculation, GFH Capital can confirm that we are in continual discussions regarding the introduction of new investment into Leeds United Football Club.
"Since acquiring ownership of the club in December 2012, we have supported the club financially, supported the manager, and worked hard to forge closer links with both the fans and the local community.
We have never made any secret about the fact that our aim has always been to attract investment partners, and we are currently speaking to a number of parties regarding the acquisition of shares.
"We would ask fans to ignore the media speculation surrounding investment, and be assured that we remain as committed as ever to the club and ensuring any new investment is in the best interests of Leeds United, for now and the future."
The statements cast further doubt over the future of the club with Cellino's intentions regarding the club unknown and another consortium, led by Manchester United director Mike Farnan, also reportedly interested in acquiring a stake.
McDermott has admitted that matters off the field have affected the team, who ended a run of five straight defeats with a 1-1 draw at home against Ipswich on Tuesday, which left them 12th in the table.
The manager was able to sign wingers Jimmy Kebe and Cameron Stewart on loan near the start of the transfer window but was forced to abandon a move for striker Ashley Barnes - who subsequently joined Burnley - amidst reports that the owners had denied him the necessary funds.