NIFTY · SESSION …SOURCE: NSE F&O BHAVCOPY · END OF DAY · ₹ CRORE
01
What DEX is
DEX, or dealer delta exposure, is the aggregate directional exposure of options positions expressed in rupees. Where GEX describes how fast dealer hedges change, DEX describes how much directional exposure there is right now.
A positive DEX means the modelled dealer book is net long the index. A negative DEX means it is net short. The dealer hedges that exposure with futures, so the figure indicates the size of the hedge already in place.
02
How DEX is computed
1. Compute delta for every call and put strike from implied volatility, time to expiry and the forward.
2. Multiply by open interest and contract lot size.
3. Apply the dealer-sign convention (exchange data does not show who is long or short).
4. Multiply by spot to express the result in rupees, then sum across strikes and expiries.
03
Reading the sign and size
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Positive DEX: The modelled book is long delta. A rally invites hedge selling, which slows the rise.
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Negative DEX: The modelled book is short delta. A rally requires hedge buying, which can add fuel.
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Size: Judge it against the same index's recent range and its futures turnover, not as an absolute number.
04
Limits
DEX depends on the dealer-sign assumption and on the volatility model. It is a snapshot that changes with spot and open interest, and it says nothing about what discretionary traders will do.
05
Frequently asked questions
What does DEX stand for?
DEX stands for dealer delta exposure, sometimes called dollar delta exposure; in the Indian market it is expressed in rupees.
What is the difference between DEX and GEX?
DEX is the size of directional exposure now. GEX is how quickly that exposure changes as the index moves.
Is negative DEX bearish?
Not by itself. It describes dealer hedging behaviour, not market direction.
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