Higher oil prices have helped the Oslo Stock Exchange's shipping index, which features maritime and offshore shares, to rise by 33.7 percent so far this year - outperforming the exchange's other indexes. Share prices of offshore shares have decreased for two months now, resisting the influence of continued buoyant oil prices. The value of shares on the Main List dropped 5.6 percent in September and 13.6 percent in October. The 19.6 percent price fall recorded by the seismic company Petroleum Geo-Services (PGS), the biggest offshore company on the Exchange, was the main contributor. The SMB-listed offshore company Ocean Rig (OCR) tops the losers list for the second month running, having sliced almost 30 percent off its share price in October. Big players such as Fred.