New Delhi: Indian stock markets registered the biggest weekly fall in over three months on Friday amidst trade tariff concerns and a sharp slump in index heavyweights.The Sensex closed at 83,576 on Friday, down 605 points or 0.7%, while the Nifty finished at 25,683, a decline of 194 points or 0.8 %. Both indices fell 2.5 % for the week, which is their steepest weekly decline since the week preceding September 26, 2025.The Business Standard reported that “the total market capitalisation (mcap) of BSE-listed firms stood at around Rs 468 trillion, down about Rs 4.5 trillion from Thursday’s close. For the week, mcap declined by Rs 13.5 trillion.”The latest fall came as concerns over US trade tariffs intensified this week, with US Senator Lindsy Graham claiming that President Donald Trump had approved a Bill that allowed tariffs up to 500% on imports from countries that buy Russian oil, including India. The Bill is also said to have made room for sanctions against such countries.Two of the best performing stocks, ICICI Bank and HDFC Bank, were hit badly by the slump this week, with the latter declining 6.3%, its sharpest fall since January 2024. Reliance Industries also fell 7.3% during the week, its biggest slump since October, 2024.Foreign portfolio investors (FPIs), too, sold their stakes with Rs 3,769 crore, making the Indian stock markets even more vulnerable. Domestic institutional players, however, saved the week by a little by buying worth Rs 5,596 crore.“There has been an escalation in tariff worries for India and geopolitical tensions, which is weighing on FPI selling. Corporate results will not have much bearing on Indian equities unless there is a positive or negative shock. Trade tariffs and global cues will determine market movement,” said U R Bhat, co-founder of Alphaniti Fintech.The paper reported that the market breadth was weak, with 3,196 stocks declining and 993 advancing.“Volatility is likely to persist in the near term, particularly in US-exposed companies and sectors such as metals and oil and gas. However, strong domestic fundamentals, resilient GDP growth, and robust credit trends could support selective buying where earnings prospects remain favourable,” said Vinod Nair, head of research at Geojit Investments.Nair said that foreign institutional flows and currency movements will have to be constantly monitored, but expressed hope that any easing of India-US trade relations will likely trigger a short-term rebound. “Overall, markets are expected to remain range-bound with a mixed bias, as investors balance external risks against domestic fundamentals,” he said.