Takafumi Horie, former boss of Japanese internet firm Livedoor who quit amid a corporate scandal, is being framed by prosecutors, his lawyer has claimed.
Mr Horie had become a friend of Japan's prime minister
Mr Horie denies violating securities laws by falsifying profit figures to boost Livedoor's share price.
The 33-year old faces a maximum of five years in jail if found guilty.
The court case is unusual because Mr Horie has pleaded not guilty. Less than 1% of trials in Japan's district courts end in acquittals.
This leads executives charged with white-collar crime to tend to plead guilty in return for a lighter sentence.
Prosecutors have alleged executives at Livedoor used "dummy" firms to purchase its shares in order to artificially boost profits.
Mr Horie's lawyer, Yasuyuki Takai, said that in cross-examinations some witnesses admitted that some of the money had gone into accounts unrelated to Mr Horie which he claimed showed his client had no link to them.
"This is a frame up," Mr Takai told the Associated Press news agency.
Mr Horie's fall from grace earlier this year sent shockwaves through the Japanese stock market, leading to a sharp fall in share prices.
The case against Mr Horie has attracted widespread public interest because his brash, aggressive manner was at odds with Japan's traditionally conservative business culture.
Four colleagues including the firm's chief financial officer have admitted their guilt but Mr Horie, whose case has taken much longer to come to court, has denied all charges.