Court authorities confirmed to the Leta news agency Monday that Latvia's ABLV Bank on June 27 lodged an appeal against Poikans' recent acquital on all charges of leaking confidential data.
Writing on his twitter feed, Poikans said he would “fight to the end” to see off the fresh attempt to convict him.
Poikans' case had attracted widespread international attention not only because his disclosures had clearly been in the public good but because the judge in the case controversially ruled that it would be heard in closed court, barring the press on grounds of commercial confidentiality.
In 2010 a whistleblower known only as 'Neo' - a pseudonym taken from the Matrix series of movies - obtained 7.5 million classified files from Latvia's tax authority, the State Revenue Service (SRS) after discovering a simple flaw in its electronic security system.
He released selected data into the public domain via investigative journalist Ilze Nagla to show that senior state employees were continuing to pocket large wages and bonuses while hundreds of lower-paid workers were losing their jobs and having wages slashed by a third as part of an austerity drive.
His disclosures included senior staff at bailed-out Parex Bank, the financial regulator, the Latvian central bank and state-owned power utility Latvenergo.
Months later, Neo's identity was revealed to be Ilmars Poikans, a researcher and computing expert at the University of Latvia. He was subsequently named Latvia's "European of the Year" in an online public vote.
In 2010 police raided the home of Nagla, the journalist who had been helping Poikans get his revelations to the public while protecting his identity.
Nagla complained to the Riga Central District Court but had her case rejected, forcing her to take it to the European Court of Human Rights (ECHR) which ruled that the Latvian state had violated the European Human Rights Convention with regard to freedom of expression and ordered that she be paid compensation of 20,000 euros.
Four years after his revelations, the case against Poikans was finally brought by ABLV bank in April 2014 when he was accused of obtaining and publishing private data. He faced a possible jail term of up to two years if convicted but was acquited on all charges on June 5.
Founded in 1993 when it was known as Aizkraukles Bank, ABLV Bank is the largest privately-owned bank in Latvia with offices in many countries of the Commonwealth of Independent States (CIS) including Russia, Ukraine, Kazakhstan, Belarus, Tajikistan, Uzbekistan and Azerbaijan.