Greek stocks headed south for the fourth consecutive session yesterday, in line with continuing negative sentiment on markets abroad. Heavyweight banks National and Cyprus bucked the trend, limiting overall blue chip losses. Trading was also interrupted by technical problems which forced the bourse to cancel a number of transactions. The Athens Exchange (ATHEX) general index declined 0.55 percent, closing at 4,788.68 points. The FTSE/ATHEX 20 blue chip index was down 0.31 percent, the FTSE/ATHEX Mid-40 lost 0.59 percent, and the FTSE/ATHEX 80 small-cap index ended a recent positive run, closing 0.51 percent down. The FTSE/ATHEX international index declined by 0.34 percent to reach 6,874.26 points. Bank of Cyprus led blue chips with gains of 1.89 percent, Titan climbed 1.65 percent, Viohalco climbed 1.50 percent and National Bank added 1.26 percent. By contrast, OTE slumped 3.77 percent on its dividend cutoff date, Eurobank tumbled 3.29 percent and Public Power Corporation finished 1.06 percent down. Turnover totaled -404.769 million, including -102.686 million in block trades. Some analysts argue that a series of share-capital increases planned this summer are depriving the market of liquidity.