A long-running prosecution against the owner of Barnsley Football Club and an IT firm has collapsed.
Patrick Cryne, 62, and three other ex-directors of iSoft were accused of conspiring to mislead investors about the firm's financial position.
The Financial Conduct Authority (FCA) said it decided to drop the case because of "procedural problems".
Mr Cryne, Stephen Graham, Timothy Whiston and John Whelan were cleared of wrongdoing.
An investigation dating back to 2006 by the Financial Services Authority, the FCA's predecessor, resulted in a first prosecution.
Mr Graham, 49, of Knutsford, Cheshire, Mr Whiston, 45, of Lymm, Cheshire, and Mr Whelan, 46, of Cheadle Hulme, Stockport, each denied a single charge of conspiring to make false statements between October 2003 and July 2006.
Mr Cryne never stood trial, due to ill health.
Jurors failed to reach a verdict in the case last year and a retrial was ordered at Southwark Crown Court but it ground to a halt.
A spokesman for the FCA said legal argument arose when old file notes dating back to 2009 were disclosed to the defence, resulting in procedural problems that could not be resolved.
'Particularly unusual circumstances'
The jury was discharged and the FCA decided that it would not be in the public interest to pursue a second retrial.
Not guilty verdicts were formally entered against all four men.
Tracey McDermott, FCA director of enforcement and financial crime, said: "This is of course a disappointing outcome.
"The problems that have arisen in this case result from a particularly unusual set of circumstances, which are unlikely to recur."
FCA's chief executive Martin Wheatley said: "This decision not to seek a second retrial does not undermine our determination to bring and prosecute difficult cases."
Mr Whelan's solicitor, Anthony Barnfather, said the case had cost the public "millions of pounds".
iSoft, a major healthcare software provider, was bought by Australian firm IBA Health in 2007 before being acquired by US group CSC.
Mr Cryne is the firm's former chairman. He owns Barnsley Football Club, and at one time iSoft was its shirt sponsor.