Net Gamma Exposure (GEX)

Net dealer gamma exposure, USD per 1% move (Deribit BTC options)

Property	Value
Category	Options
Unit	USD
Resolution	1d
Assets	BTC
Tier	Pro
API Endpoint	GET /v1/options/gex
Field	net_gex

Overview

Net gamma exposure (GEX) measures how much delta options dealers must trade, in USD, for every 1% move in the BTC price. Dealer inventory per option is rebuilt from the full Deribit trade tape since listing: dealers are assumed to take the other side of every taker trade, so inventory = taker sells − taker buys. Gamma is recomputed with Black-Scholes from each expiry's forward (zero rate, implied volatility and time to expiry held fixed). Net GEX is the sum over all calls and puts at the current price.

Formula

$\text{GEX}(P) = \sum_i \text{inv}_i \, \Gamma_i(P) \, \frac{P^2}{100}, \qquad \text{Net GEX} = \text{GEX}(S)$

• $\text{inv}_i$ — dealer inventory of option $i$ in BTC (taker sells minus taker buys since listing)
• $\Gamma_i(P)$ — Black-Scholes gamma of option $i$ at price $P$; $S$ — current BTC index price

Interpretation

• Positive: dealers are net long gamma. To stay hedged they sell rallies and buy dips, which tends to compress volatility and pin the price.
• Negative: dealers are net short gamma. Their hedging chases the price, which tends to amplify moves in both directions.
• The size matters as much as the sign: GEX is USD of hedging per 1% move, so it compares directly with spot liquidity.
• The value is a model of dealer positioning from public trades, not a reported dealer book.

Use Cases

• Classify the volatility regime (mean-reverting long gamma versus trending short gamma).
• Read with the Zero Gamma Level: the distance from the price to zero gamma shows how far the regime is from flipping.
• Size the hedging flow of a move with the Dealer Hedge Flow at ±5% / ±10% metrics.

Data Notes

• Daily value = the 00:00 UTC hourly snapshot of the day (the first snapshot of the day if 00:00 is missing), away from the 08:00 UTC daily expiry; a day's value does not change once published. Every hourly snapshot is available from /v1/options/gex/hourly, the full price profile from /v1/options/gex/profile.
• History starts on 2026-03-16 (hourly snapshots of the options board); about four weeks in June 2026 are missing (collection outage). Dealer inventory is summed over each option's full trade history since listing, so early values are not a cold start.
• Deribit BTC options only; other venues are not included.

API Usage

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.blocklens.co/v1/options/gex?start_date=2024-01-01&end_date=2024-12-31&limit=365"

Related Metrics

• Zero Gamma Level — Price where net dealer gamma changes sign (Deribit BTC options)
• Dealer Hedge Flow at +5% — Dealer hedge flow in USD if BTC moves +5% (Deribit options)
• Dealer Hedge Flow at −5% — Dealer hedge flow in USD if BTC moves −5% (Deribit options)