Expected move: what the ATM straddle is telling you before you trade
Before the first candle prints, the option market has already priced how far it expects the index to travel. That price is the ATM straddle: one call plus one put at the strike closest to spot.
From straddle to range
A straddle prices roughly 0.8 of a one-standard-deviation move to expiry. So 1σ ≈ straddle ÷ 0.8. For a single day, use implied volatility instead: expected day move = spot × IV × √(1/252). With NIFTY at 23,400 and IV at 14%, that is about 206 points, a 1σ band of 23,194 to 23,606.
Why it matters
Every strategy is a bet on realised versus expected. Sellers earn when the day stays inside the band; buyers need it to break out. Knowing the band turns "the market moved 150 points" into "the market moved 0.7σ, well inside what was priced" — a very different sentence.
Realised versus expected
By 11:00 you can already compare today's high–low range against the 2σ-wide expected range. Under 60% and it is a quiet day where theta wins; over 120% and straddles are paying, so fresh short premium is dangerous. The terminal's MOVE panel draws the band on today's path and updates the ratio every 30 seconds; the daily expiry brief carries the morning number.
What sellers do with it
Strikes at or beyond the 1σ band collect premium with a statistical edge on a normal day. The VIP Indicator option-selling engine uses exactly this: it takes the expected move, the dealing range and the nearest supply and demand, and prints the call and put strikes on the chart, with a STAND ASIDE when the tape is expanding.