LONDON (ICIS)--Higher petrochemical and polymer prices in northeast Asia in October helped lift the global ICIS Petrochemical Index for the month, data showed on Friday. The global IPEX, which represents price movements of a basket of 12 petrochemicals and polymers in three regions – northeast Asia, the US and northwest Europe – was 1.7% higher at 229.82. The index is related to a January 1993 base and weighted by capacity. The northeast Asia index was up 4.2% for the month while the US index was flat. The northwest Europe index fell 1.6%. The global index was 10% higher in October year on year. Oil prices moved higher in the first half of October before dropping back later in the month. Petrochemical prices tend to follow crude and move largely on a spot basis in northeast Asia with some monthly contracts. The IPEX is based on monthly contracts in the US and northwest Europe. The index is calculated in US dollars while northwest Europe prices are agreed in Europe. The euro weakened against the dollar by 1.9% on average over the course of the month. Ethylene prices were down in all regions in October while propylene prices were down in northeast Asia and the US but up in Europe in US dollars. Butadiene and methanol prices were higher in all regions in dollars. The regional and global IPEX monthly values can be subject to change as monthly contract prices are agreed in the regions. For October 2016 the only regional IPEX contract price not to settle was US styrene. The 12 petrochemicals in the IPEX basket are ethylene, propylene, butadiene, benzene,toluene, paraxylene, styrene, polystyrene (PS), polyethylene (PE), polypropylene (PP), methanol and polyvinyl chloride (PVC). The regional and global IPEX monthly values can be subject to change as monthly contract prices are agreed in the regions. For September 2016 the only regional IPEX contract prices not to settle were US styrene and styrene in northeast Asia.