The first hour of the Indian market often sets the tone for the day. Overnight news gets priced in, big players build their positions, and support and resistance levels for the session start to form. If you can read how open interest changed in that first hour, you start the rest of the day with a much clearer map.

This guide explains what to look for in the opening session, and how to compare OI changes for different parts of the day using the OPIFY Option Scanner.

What happens in the first 15 minutes

The opening minutes are the noisiest part of the day. Prices react to the overnight gap, spreads are wider, and both buyers and sellers are adjusting. OI changes here are useful, but they can reverse quickly.

Use the First 15 min window to see where the initial positioning went, but don't treat it as final.

The first hour: where the day's levels form

By 10:15, most of the opening noise has settled. The First hour window shows a more reliable picture:

• Calls with short buildup near the money: writers think the index won't go above those strikes. Possible resistance.
• Puts with short buildup near the money: writers think the index won't go below. Possible support.
• Short covering on calls: call writers are exiting, often because the market is moving up through their levels.
• Short covering on puts: put writers are exiting during a fall.

After the first hour: is the opening view holding?

Switch to the After first hour window. Now you're checking whether positions taken early are being added to or abandoned.

The afternoon and last hour

Use Since 12:00 to see how positions changed in the second half, and Last hour to see end-of-day activity. On expiry days in particular, the last hour can show large unwinding as positions are closed.

Step by step on OPIFY

1. Open the Option Scanner and choose NIFTY, BANKNIFTY or SENSEX.
2. Select First hour, Both options and Near ATM strikes.
3. Sort by Largest OI change (qty) and note the top call and put strikes.
4. Switch to After first hour and compare the labels.
5. Use Compare to put two windows side by side.

Combine with the OI chart and spot chart

The scanner shows what changed. To see the total positioning per strike, open the OI chart. To check whether price agrees with the OI story, look at the spot chart.

Common mistakes

• Reacting to the first five minutes as if it were the day's trend.
• Ignoring the gap. A big gap-up or gap-down changes how writers behave.
• Reading OI without price. Always check which buildup type it is.
• Forgetting that expiry days behave differently.

Frequently asked questions

Can I compare any two time windows?

Yes. Use the quick picks or set a custom From/To range.

Does this work for SENSEX?

Yes. The scanner covers NIFTY, BANKNIFTY and SENSEX.

This article is for education only and is not investment advice. Options trading involves risk.