KARACHI: The Pakistan Stock Exchange (PSX) on Thursday extended its positive momentum for the third session in a row, as select value buying helped the benchmark KSE 100 index briefly cross the 185,000 milestone in intraday trading amid persistent economic optimism. However, late profit-taking trimmed some of the early gains. Topline Securities Ltd said the benchmark KSE-100 index extended its gains on Thursday, closing at 184,520.96 points, up 470.86 points, or 0.26 per cent, from the previous session.