A day after massive selling, buying returned to the Pakistan Stock Exchange (PSX), with the benchmark KSE-100 Index gaining nearly 600 points during the opening minutes of trading on Tuesday. At 9:50am, the benchmark index was hovering at 171,157.75, up by 557.55 points or 0.33%. Buying was observed in key sectors, including automobile assemblers, cement, commercial banks, oil and gas explor