Economic prosecutors will summon 60 people in a new investigation into the funding of political parties in the period from 2002 until 2012.
The probe will focus on about 50 former banking executives and 10 party cadres for possible breach of faith and instigation to breach of faith, respectively.
The loans in question, exceeding 270 million euros, were granted by bankers of the now-defunct ATEbank and the National Bank of Greece (NBG) mainly to PASOK and New Democracy and – to a lesser extend - to the Communist Party.
Ruling SYRIZA is not being investigated because its loans are deemed as being serviced.
A law passed by the Greek parliament in 2013 protects bank employees who approved loans for political groups from any criminal charges, yet sources from the prosecutor's office told Kathimerini the reopening of the case will mainly focus on whether the law was properly implemented.
The same case was looked into by authorities in 2013 and closed without pressing charges.
Prosecutors are basing their new case on a report compiled in 2017 by a parliamentary inquiry for further investigation.