FNB has alerted authorities about the "unlawfully placed" banner, Virginia Magapatona, FNB corporate affairs executive said in an emailed statement. However the bank was not able to give further comment on the matter.
The banner has defaced the FNB logo with an AK-47 instead of the Acacia tree. The use of the rifle suggests that the banner is linked to recent reports on of burglaries at FNB branches targeting safety deposit boxes.
The first heist took place on 18 December 2016, where more than 300 safety deposit boxes were stolen from the Randburg branch. Two days later, a tip-off led police to discover 250 boxes in a field near the FNB stadium in the south of Johannesburg.
There was another break in on New Year's eve at the bank's Parktown branch in which two bank vaults were opened and R1.7m and valuables which were inside 30 safety deposit boxes were stolen.
A number of victims opened up to Fin24 about their losses. One customer lost all her life savings, including a gift that was given during World War II.
One user recalled the painful killing of her father during a house robbery that led her mother to renting a safety deposit box from FNB to protect the valuable items that the thieves didn't get to. Another victim with a 40-year-old coin collection said her loss was irreplaceable. The banner also made the rounds on social media.