All indices of the Bulgarian Stock Exchange closed the week in negative territory as trading remained subdued, stock exchange data showed. The bourse's benchmark SOFIX index inched down 0.07% to 595.31 points and the wider BGBX40 index, which tracks the 40 most traded shares on the Sofia bourse, lost 0.39% to 116.65 points. Turnover on the regulated market totalled 337,000 levs ($196,400/172,300 euro). Industrial group Stara Planina Hold led the blue-chip losers with a 2.94% drop to 6.6 levs. On the opposite end, civil engineering company Trace Group Hold was the biggest blue-chip gainer, appreciating 5.63% to 3.00 levs in a volume of 215 shares, after hitting a six-year low a day earlier. Another blue chip to buck the negative trend was software developer Sirma Group Holding, which extended its seven-day winning streak, adding a further 1.52% to 0.9 levs in a healthy volume of 66,580 shares.