Yes Bank and Union Bank to Join Nifty Bank Index from 31 December Amid Weight Cap Overhaul

Mumbai, 03 December 2025: Yes Bank and Union Bank of India are set to enter NSE’s Nifty Bank index from 31 December 2025, expanding the benchmark from 12 to 14 stocks. The change follows directives from the Securities and Exchange Board of India (SEBI) mandating broader representation in non-benchmark indices eligible for derivatives trading.

Nifty Bank Expansion to 14 Constituents Reduces Top-Three Stock Weight from 60% to 43%

The inclusion of Yes Bank and Union Bank is part of SEBI’s requirement that banking indices such as Nifty Bank, Finnifty, and BSE Bankex must comprise at least 14 stocks. In addition, SEBI introduced weight caps for the top three constituents — HDFC Bank, ICICI Bank, and State Bank of India (SBI) — to limit concentration risk.

Currently, these three banks hold a combined weight of 60% in the index. The rebalancing will reduce this to 43% over four monthly tranches from December 2025 to March 2026, creating potential outflows from passive funds such as index and exchange-traded funds (ETFs) tracking Nifty Bank.

HDFC and ICICI Face Reductions, SBI Slight Increase; Yes Bank and Union Bank to Receive Inflows

According to Nuvama Alternative & Quantitative Research, the index reshuffle could trigger outflows of approximately $670 million from HDFC Bank and ICICI Bank by March. SBI is expected to receive modest inflows of $31 million, while the two new entrants, Yes Bank and Union Bank, could see total inflows of $249 million.

This move to cap the influence of dominant stocks may have been prompted by prior market events, including allegations against the US trading firm Jane Street for manipulating Bank Nifty derivatives. The revised weights are designed to enhance diversification and reduce the potential for any single stock to disproportionately impact index performance.

Individual Stock Weight Adjustments to Alter Index Composition by March 2026

Current weights in Nifty Bank will change as follows:

• HDFC Bank: from 27.5% to 18.9%
• ICICI Bank: from 23.1% to 14%
• SBI: from 9.4% to 10%

The monthly tranche adjustments ensure a phased realignment, reducing market disruption and allowing funds to rebalance portfolios gradually in accordance with the new index methodology.

Union Bank and Yes Bank Shares See Early Movements Following Announcement

The share price of Union Bank of India (NSE: UNIONBANK) opened at ₹157.34 and hit a high of ₹157.70, before sliding to a low of ₹152.12. As of 10:59 am IST, the stock traded at ₹152.26, down ₹3.51 (2.25%), reflecting early market reaction to its upcoming Nifty Bank inclusion.

Yes Bank share price (NSE: YESBANK) opened at ₹22.85, reaching a high of ₹22.87 and a low of ₹22.32, and was trading at ₹22.34 as of 11:00 am IST, down ₹0.37 (1.63%). The moves indicate short-term price adjustments as market participants factor in the scheduled index changes and potential passive fund flows.

Regulatory Push and Structural Impact: Why Nifty Bank Is Being Rebalanced

The Nifty Bank overhaul seeks to expand the index’s breadth and reduce concentration risk. By limiting the top-three banks’ weight to 43% and adding Yes Bank and Union Bank, the index is positioned for broader sector representation. The changes also ensure that derivatives trading is based on a more balanced benchmark, reducing the potential for manipulation while increasing the index’s robustness as a market indicator.

The inclusion of Yes Bank and Union Bank in Nifty Bank, along with phased top-stock weight reductions, reflects SEBI’s efforts to strengthen index structure and diversify sector representation. The adjustments will be implemented from December 2025 through March 2026, affecting index composition and requiring portfolio rebalancing by funds tracking the benchmark.

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