Most stocks posted gains for yet another day yesterday but National Bank losses dragged the main index slightly lower for the first time after four sessions with profits. The Athens Exchange (ATHEX) general index closed at 1,586.11 points, contracting 0.19 percent from Wednesday’s close at 1,589.15 points. The blue chip FTSE/ THEX 20 index shrank 0.64 percent to end at 771.78 points. Nevertheless, the mid-cap index expanded by 0.99 percent. National Bank gave up 2.84 percent to lead the losing blue chips, followed by Bank of Cyprus (down 1.47 percent) and Titan Cement (1.30 percent). Ellaktor posted the biggest gains among the FTSE/ATHEX 20 index stocks, adding 4.46 percent. A total of 100 stocks headed north, 70 went down and 46 remained unchanged. Viokarpet led the gainers with a 19.72 percent rise, while construction firm Edrasi suffered the biggest losses, falling 15.38 percent. Turnover came to 105.8 million euros, up from Wednesday’s 90 million.