> ## Documentation Index > Fetch the complete documentation index at: https://docs.backquant.com/llms.txt > Use this file to discover all available pages before exploring further. # Dealer positioning: flow vs std > How GEX and TRACE sign dealer exposure, multi-venue aggregation, and when each model applies Dealer exposure needs a **sign** at every contract: is the desk long or short that option's gamma? Two models are available on the live GEX and TRACE surfaces. ## Models | Mode | Meaning | When to use | | -------------------- | -------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------- | | **`flow`** (default) | BackQuant's measured dealer model, derived from observed trading rather than an open-interest assumption | Best match to how price behaves where the model is available (BTC, ETH) | | **`std`** | Textbook convention: call OI positive, put OI negative | Backtests, comparisons to public GEX, or symbols without usable tape | Pass `?positioning=flow` or `?positioning=std`. Omit the param to get **flow**. Every response that rebuilds live exposure reports the effective model in: * `data.positioning` when present * `meta.extra.positioning` and `meta.extra.positioning_requested` * `meta.extra.positioning_fallback_reason` when flow was requested but std ran instead ## Aggregation Live signed surfaces use: Both models read the same multi-venue options chain for greeks and **coin-unit OI**: Deribit, Bybit, OKX, Binance, Derive (when enabled), Thalex, Delta India and Delta Global. See [Venue coverage](/concepts/venues) for what each venue contributes. GEX is reported in **USD impact per 1% move in spot**, so magnitudes are comparable across symbols and across both models. `meta.extra.aggregation` echoes which venues were combined for the response. ## Coin coverage | Symbol | Flow tape | Default behaviour | | ----------------- | ----------------------------------- | --------------------------------------------------------------------------- | | BTCUSDT, ETHUSDT | Yes (multi-venue) | Flow when tape is non-empty | | SOLUSDT, HYPEUSDT | When Derive (or other) tape is live | Falls back to **std** if no aggressor tape (`no_aggressor_tape_for_symbol`) | If flow is empty for BTC/ETH, the API falls back to std and sets `meta.extra.positioning_fallback_reason` (for example `flow_tape_empty` or `flow_qty_all_zero`). ## Live vs history | Surface | Positioning | | ------------------------------------------------------------------------------------- | ------------------------------------- | | Levels, strike profile, expiry profile, heatmaps, TRACE, multi levels, greek profiles | **flow** default | | `/v2/gex/history`, `/v2/gex/stress-history` | **std** only (stored series) | | WebSocket `gex.levels.{SYMBOL}` | **flow** default, same as REST levels | | Max pain, IV, PCR, OI, expected move, probability | Not a signed dealer model | ## Customer flow vs dealer hedge flow Do not mix these up: | Endpoint family | Side | Source | | ------------------------------------------- | -------------------------------------------- | ------------- | | `/v2/gex/delta-flow`, tape `weight=delta` | **Customer** signed delta from trades | Options tape | | `/v2/tape/flow-by-strike` | **Aggressor** activity by strike | Options tape | | `/v2/gex/gamma-flow`, `/v2/gex/dealer-flow` | **Dealer** hedge estimate from chain × moves | GEX snapshots | Positive on dealer-flow ≈ estimated dealer **buying** the underlying to re-hedge. Positive on delta-flow ≈ net **customer** buy-side delta notional. ## Related