SBI NIM Squeeze Triggers PSU Bank Selloff

SBI NIM Data Rattles PSU Bank Investors State Bank of India's Q4 FY26 results landed like a warning shot on Dalal Street. Net Interest Margins contracted, and the market's reaction was swift and unambiguous. [SBI](/stock/SBIN) (NSE: SBIN) shares fell 7% in a single session, one of the steepest single-day drops for India's largest public-sector lender in recent memory. The Nifty PSU Bank index shed 3.06%, and the Sensex closed 516 points lower as heavyweight banking stocks faced relentless selling pressure through the session. NIM compression at SBI isn't just an accounting footnote. Net Interest Margin is the spread between what a bank earns on loans and what it pays on deposits. It's the core engine of bank profitability. When that spread narrows, earnings power erodes, and equity valuations follow. SBI's Q4 report has now raised a question that every PSU bank investor is asking: is this an SBI-specific problem, or the start of a sector-wide squeeze? The answer matters enormously. PSU banks carry significant weight in both the Nifty 50 and broader midcap indices. A systemic NIM contraction across the sector would recalibrate earnings forecasts for the entire cohort, and that recalibration is already beginning. Which PSU Bank Stocks Are Now Under Pressure The selloff didn't stay contained to SBI. [Punjab National Bank](/stock/PNB) (NSE: PNB) and [Bank of Baroda](/stock/BANKBARODA) (NSE: BANKBARODA) both saw heavy volume-driven declines as traders repositioned ahead of their own Q4 results. Canara Bank (NSE: CANBK) and Union Bank of India (NSE: UNIONBANK) were similarly caught in the downdraft, with investors unwilling to hold through earnings uncertainty when the sector's largest player has already flagged margin stress. The structural backdrop matters here. Over the past 18 months, PSU banks benefited from a favorable rate cycle. Elevated lending rates supported NIMs while deposit costs lagged. That dynamic is now reversing. The Reserve Bank of India has move...