Shares closed marginally higher, but on extremely low volume as the power blackout earlier affected trade, dealers said. The Athens Stock Exchange general index ended up 0.03 percent at 2,332.15, and while the blue-chip index rose 0.04 percent to 1,241.63, the mid-cap index gained 0.17 percent and the small-cap index retreated 0.24 percent. Energy monopoly PPC finished 2.70 percent higher to 19 euros, as a note from CSFB earlier offset concerns after yesterday’s blackout about power efficiency ahead of the Olympic Games next month. In fact, PPC’s turnover (21.3 million euros) accounted for more than a third of the total turnover of 62.8 million. Insurance stocks gained 5.69 percent and holding companies 1.12 percent. Textiles dropped 2.69 percent and information technology stocks 1.72 percent. Banks moved 0.14 percent up, with National Bank of Greece rising 0.23 percent to 17.26 euros, Alpha Bank 0.48 percent higher to 20.82 euros and Eurobank up 0.34 percent to 17.54 euros. Telecoms group OTE declined 0.77 percent to 10.28 euros, while subsidiary CosmOTE ended flat at 12.70 euros. Lottery operator OPAP finished 1.25 percent lower to 15.80 euros. Of the 343 stocks traded, 147 stocks ended lower, while 135 rose and 61 remained unchanged.