Tuesday's trading session at the Pakistan Stock Exchange (PSX) turned into one of the most brutal sell-offs in recent memory, with the benchmark KSE-100 index shedding over 6,400 points as renewed hostilities between the United States and Iran rattled investors worldwide. The decline, which accelerated sharply after 2:30pm, erased billions in market value and pushed the index below the psychological threshold of 180,000 points for the first time in weeks. Main Developments The KSE-100 index opened in negative territory and had already lost 3,464.89 points by 10am, falling to 176,462.15 from the previous close of 179,927.04. After minor fluctuations during the day, a steep decline began after 2:30pm, culminating in a closing figure of 173,518.81—a drop of 6,408.23 points or 3.56%. The sell-off was broad-based, with cyclical sectors suffering the heaviest losses. According to Topline Securities Ltd, the largest negative contributors were United Bank Limited (UBL), Engro Holdings, Fauji Fertiliser Company, Lucky Cement, and Meezan Bank, which collectively shaved 2,057 points off the benchmark index. Read also: Pakistan Orders Full Digitisation of Overseas Remittances Awais Ashraf, director of research at AKD Securities, noted that the crash directly followed the US reinstating its naval blockade of Iran. “The decline is broad-based, with cyclical sectors witnessing the sharpest percentage losses amid heightened uncertainty over the medium-term outlook due to the emerging geopolitical situation,” he said. Background The turmoil traces back to the collapse of an interim peace arrangement between the US and Iran, which had been formalized through a memorandum of understanding signed on June 18. That agreement had temporarily calmed markets and helped stabilize oil prices. The renewed fighting involves the US reimposing a naval blockade and conducting airstrikes, while Iran has responded by targeting oil tankers transiting the Strait of Hormuz. Oil prices surged to their highest in four weeks on Tuesday, with Brent crude futures rising $2.89 (3.47%) to $86.19 per barrel at 5pm PKT, and US West Texas Intermediate crude climbing $1.53 (1.96%) to $79.67 a barrel. The Strait of Hormuz is a critical chokepoint for global energy flows, and any disruption there directly impacts fuel costs worldwide. The PSX had already come under pressure on Monday, when the KSE-100 index fell 2,314 points (1.27%) to close at 179,927, breaking below the 180,000 barrier. That decline was exacerbated by broad-based profit-taking after the market's recent rally, as investors chose to lock in gains despite an otherwise supportive macroeconomic backdrop. Why It Matters The scale of Tuesday's losses—the largest single-day point drop in recent memory—signals that Pakistani equities are highly vulnerable to geopolitical shocks beyond domestic control. For ordinary investors, the erosion of market value means diminished retirement savings and portfolio losses at a time when the economy is still recovering from previous shocks. Broader implications extend to the national economy: a sustained market downturn could dampen investor confidence, slow capital formation, and make it more expensive for companies to raise funds through equity markets. The spike in oil prices also threatens Pakistan's import bill and foreign exchange reserves, given the country's heavy reliance on imported energy. What's Next Global markets are already reflecting the uncertainty. European shares opened lower, with the pan-European STOXX 600 index slipping 0.4%, while S&P 500 futures ticked 0.1% lower in early trading. Asian markets showed mixed results—Chinese shares surged 2.15% on strong trade data, but Taiwan's stocks fell 1.42%. The US dollar index nudged 0.1% lower to 101.16, while gold—a traditional safe-haven asset—rose 0.5% to $4,020.34, suggesting investors are hedging against further geopolitical instability. In Tokyo, the Nikkei 225 closed 0.7% higher after Japan's finance minister hinted at possible adjustments to the Government Pension Investment Fund's strategy. For Pakistani markets, the trajectory depends heavily on whether the US-Iran confrontation escalates or de-escalates in the coming days. Any diplomatic breakthrough could trigger a sharp recovery, while continued hostilities risk further selling pressure on the PSX and higher energy costs for the economy.