Simple CAS Prediction Method (Before 3:30 PM) - Sensex, Nifty, Bank Nifty

 

Simple CAS Prediction Method (Before 3:30 PM)

Purpose

After 3:15 PM, the Sensex cash chart stops moving because of the Closing Auction Session (CAS).

To estimate where Sensex is moving, watch the ATM or 1 ITM Call Option.

---

Step 1 – At 3:15 PM

Example:

• Sensex = 78,785
• ITM Strike = 78,700 CE
• Option LTP = 365

Calculate:

Intrinsic Value

= 78,785 − 78,700

= 85

Extrinsic Value

= 365 − 85

= 280

Remember only one number: 280 (Extrinsic).

---

Step 2 – During CAS (3:16–3:30 PM)

Watch only the option price.

Formula:

Estimated Sensex

= Strike + Current Option Price − 280

---

Example 1

Option = 390

Sensex

= 78,700 + 390 − 280

= 78,810

---

Example 2

Option = 425

Sensex

= 78,700 + 425 − 280

= 78,845

---

Example 3

Option = 500

Sensex

= 78,700 + 500 − 280

= 78,920

---

Quick Rule

If the option price rises by:

+20 points → Sensex is approximately +20 points

+50 points → Sensex is approximately +50 points

+100 points → Sensex is approximately +100 points

As long as the extrinsic value stays nearly the same, every 1-point move in the option roughly corresponds to a 1-point move in the index.

---

Easy Memory Trick

At 3:15 PM:

✔ Note the Sensex level.

✔ Note the option LTP.

✔ Calculate and remember only the Extrinsic Value.

From 3:16 PM to 3:30 PM:

Estimated Sensex = Strike + Option LTP − Extrinsic

---

Example Summary

Time	Option LTP	Estimated Sensex
3:15	365	78,785
3:16	390	78,810
3:17	425	78,845
3:18	450	78,870
3:20	500	78,920

---

Important Note

This method estimates the current Sensex value during CAS. It does not predict the final closing price by itself. The final CAS close depends on the buy and sell orders matched in the closing auction, so the actual close can still differ slightly from the estimate.