A roller-coaster session at the local bourse yesterday saw the main index close higher, mostly thanks to increases registered by the stocks of National Bank, OTE telecom and OPAP. The Athens Exchange (ATHEX) general index closed at 2,327.57 points, rising by 0.76 percent from Thursday’s close at 2,310.11 points. The blue chip FTSE/ATHEX 20 index expanded by 0.97 percent to end up at 1,202.91 points. Titan cement had the best performance among blue chips, with a 3.51 percent rise, followed by Mytilineos (up 3.32 percent), OPAP (2.93 percent), National Bank (2.65 percent) and OTE (2.11 percent). Intralot lost 4.74 percent and Viohalco shed 1.93 percent. Turnover amounted to 211.7 million euros, down from 256 million on Thursday.