Once again yesterday, stocks in the local bourse swung from positive to negative territory during the day, with those closing with losses edging out those that gained. The Athens Exchange (ATHEX) closed at 3,427.07 points, posting a 0.34 percent fall from Wednesday. The blue chip FTSE/ATHEX 20 index dropped by 0.58 percent to 1,879.51 points, but the small-cap FTSE/ATHEX 80 index posted a rise of 0.22 percent. Hellenic Petroleum gained 3.89 percent on its better-than-expected first-half results, followed by Marfin Popular Bank (up 3.48 percent) and Coca-Cola HBC (2.97 percent). Piraeus Bank was the worst off among blue chips with a decline of 5.03 percent. Turnover reached 224.7 million euros. In July, foreign investors marginally increased their stakes in local stocks, reaching 51.6 percent from 51.5 percent in June.