Balasore's Additional District Judge Gyanaranjan Mohanty extended Kundu's custody with EOW on his production before him after the lapse of his earlier five-day custody with the agency.
The EOW had earlier been granted Kundu's custody in a different case related to the scam.
Kundu had been chargesheeted by the CBI in the chitfund scam and arrested in March 2015 in Kolkata. He has been in jail since then and was brought here for questioning earlier this year.