New Delhi, Aug. 28 -- The Indian stock market is poised for a test of resilience on Thursday, as a new round of US tariffs and the monthly derivatives expiry threaten a bout of volatility.

Stocks slumped 1% on Tuesday after the US slapped an extra 25% tariff on nearly all Indian goods, raising overall duties to as much as 50%-among the highest Washington has imposed on any trading partner. The market remained closed on Wednesday for Ganesh Chaturthi, making Thursday the opening day for investors in the punitive tariff regime.

Adding to the pressure is the monthly futures and options expiry, which typically falls on the last Thursday of the month. As traders roll over their positions to the next month's series, the pace and cost of these...