SHENZHEN, Guangdong, July 8 -- China's Supreme People's Court (SPC) reopened one of the country's biggest insider trading cases on Wednessday after procurators protested lenient penalties handed out by lower courts.

Wednesday's public trial of Ma Le, a former fund manager of Bosera Asset Management Co. Ltd, one of the largest fund houses in China, was held in Shenzhen at the SPC's No.1 circuit court in the presence of Ma's relatives, representatives of Shenzhen residents, and lawmakers, a SPC statement said.

Ma was sentenced to three years with a five-year reprieve for insider trading by the Shenzhen Intermediate People's Court in March last year for purchasing stock shares using non-public information.

He illegally earned 18.83 million yuan (about 3 million U.S. dollars), making his case the largest monetary insider trading case at the time. All money was confiscated and Ma was fined an additional 18.84 million yuan.

According to the Criminal Law in China, traders who take advantage of non-public information in stock market transactions could face imprisonment of up to five years and fines of up to five times their illegal gains in serious cases. The prison terms can be extended up to ten years in particularly serious offences.

The Shenzhen court said Ma chose to turn himself in, repented his crimes and was able to return all illegal gains and pay his fines. His actions were behind the lenient penalties, but prosecutors disagree.

Shenzhen procurators protested the initial verdict one month later in April 2014, asserting that the penalty was "inappropriate".

The Shenzhen court's ruling was upheld in October by the Guangdong Provincial Higher People's Court and prosecutors from the Supreme People's Procuratorate protested it again two months later - this time, to the SPC.

Wednesday's SPC circuit court did not immediately give its final ruling, which will be released on due date, the court statement said.