A finance director and two lawyers have been cleared of insider dealing.
Lawyers Michael McFall, 43, and Andrew Rimmington, 40, were accused of making £80,000 by buying shares in NeuTec Pharma ahead of a takeover by Novartis.
They were accused at Southwark Crown Court of receiving inside information from Andrew King, a NeuTec director.
Mr McFall and Mr King, of London, were cleared by jurors. Mr Rimmington, of Hampshire, whose trial was on hold due to a bereavement, was also acquitted.
During the trial, the court heard NeuTec, a small biotech firm, was subject to a large corporate £305m buyout by Novartis in June 2006.
The deal saw founders Prof James Burnie and Prof Ruth Matthews legitimately receive about £21m for the business they set up at the University of Manchester in the late 1990s.
But chief prosecutor Michael Bowes QC claimed Mr McFall and Mr Rimmington had made "substantial" illegal profits after being tipped off prior to the buyout by Mr King - a friend of Mr McFall and NeuTec's financial director.
The prosecution claimed Mr McFall, of Bennerley Road, Battersea, and Mr Rimmington, of Childerstone, Liphook, had been "desperate" to put cash into the company shortly before it was taken over.
The defence said Mr King's passion for NeuTec must have simply rubbed off on his friends, who then decided to purchase shares.
Last week, Mr Rimmington's trial was stopped when judge Peter Testar was told the defendant's brother had died 12 days after being attacked on 15 May.
After jurors returned not guilty verdicts for his two co-defendants, the Financial Services Authority - which brought the prosecution - decided not to pursue the case against him, and Mr Rimmington was cleared.
Mr McFall had denied five counts of insider dealing, Mr Rimmington denied three, while Mr King, of The Chase, Clapham, denied one count.
They had faced a maximum sentence of seven years in jail.
Margaret Cole, the Financial Services Authority's director of enforcement and financial crime, said: "Insider dealing cases are challenging to prove, but these were serious charges and we considered that the evidence provided a proper basis to put the case before a jury for them to decide."