"The Bank Nifty Index witnessed a sideways trading session on the day of the weekly expiry and was unable to surpass the 50000 mark, where the highest open interest is built up on the call side. The index needs to decisively surpass the 50000 mark to gain further momentum towards the 50500/51000 levels. The lower-end support is placed at 49400, and a break below this level will accelerate further selling pressure towards the 49000 mark."