The Athens General stock market index recorded a marginal increase of half a percentage point during the opening session on Thursday, standing at 568.25 points. Trading volume stood at 3.45 million Euros, with National Bank opt Greece (NBG) making 1.05% gains at 0.192 Euros per share and Piraeus bank opening at 0.134 Euros, a 0.75% rise. The large cap index was slightly down by 0.02%, while the medium cap index was up by 0.64%. Technology and banking stocks registered the highest rise with +0.67% and +0.63%, respectively.