# BingX VST Maker Fee Measurement

> ## ⚠ VERIFIED VERDICT (Fable, 2026-07-14) — the fee is **+2.00 bps (a COST), not a rebate**
>
> omp's raw capture below is **correct and valuable**; only the *sign interpretation* is wrong.
> BingX reports `commission` with a **negative sign to denote a debit** (money leaving your
> account) — the opposite of Binance. `commission: "-0.001291"` therefore means the account
> **paid** 0.001291 USDT, i.e. a **fee of +2.00 bps**, not a −2.00 bps rebate.
>
> Two independent proofs it is a cost, not a rebate:
> 1. **Magnitude is exactly BingX's published maker rate.** `0.001291 / 6.45475 = 0.020001%`
>    = **0.02%** to five figures — the standard tier-0 BingX perp maker fee. No venue *pays*
>    a 2 bp maker rebate at retail tier.
> 2. **The repo's own friction kernel treats commission as additive cost.** `prod/bingx/friction.py:196`
>    `net_friction_quote = actual_fee_quote + slippage`; the live-sweep doc reports
>    `Total captured fees $2,595.69 = sum(commission_quote)` as fees the venue **captured from us**.
>
> **Corrected economics for the spec:** the §0 savings table assumed **1 bp** maker. Measured is
> **2 bp** maker. Maker-both round-trip = **~4 bp** (2+2) vs taker round-trip **~10 bp** (5.016×2).
> The savings case **survives** (~6 bp/RT saved) but the per-side maker number **doubles vs the
> assumption** — it is NOT a 3× improvement, and there is **no rebate**. Update SPEC §0 accordingly.
> _(n=1; a second fill still worth capturing to confirm.)_

**Timestamp:** 2026-07-14T19:18:28.479849+00:00

**Order Details:**
- Symbol: BTCUSDT
- Side: BUY
- Order Type: LIMIT
- Time In Force: GTX
- Order ID: 2077110460164870144
- Client Order ID: gtx-fee-1784056699

**Fill Details:**
- Fill Price: 64547.5
- Fill Quantity: 0.0001
- Notional: 6.45475 USDT
- Commission: -0.001291 USDT  ← BingX sign convention: **negative = debit (a cost we paid)**

**Measured Maker Fee: +2.00 bps** (magnitude `2.000077…` bps; sign corrected from omp's `-2.00 bps`)

**Comparison:**
- Assumption (maker), SPEC §0: 1 bp  → **REFUTED, real is 2 bp (2× the assumption)**
- Measured taker baseline: 5.016 bps
- This measurement (maker): **+2.00 bps cost** (= BingX published 0.02% maker rate, confirmed)

**Raw Venue Response:**
```json
{
  "symbol": "BTC-USDT",
  "orderId": 2077110460164870144,
  "side": "BUY",
  "positionSide": "BOTH",
  "type": "LIMIT",
  "origQty": "0.0001",
  "price": "64547.5",
  "executedQty": "0.0001",
  "avgPrice": "64547.5",
  "cumQuote": "6",
  "stopPrice": "",
  "profit": "0.0000",
  "commission": "-0.001291",
  "status": "FILLED",
  "time": 1784056699000,
  "updateTime": 1784056707000,
  "clientOrderId": "gtx-fee-1784056699",
  "leverage": "3X",
  "takeProfit": {
    "type": "TAKE_PROFIT",
    "quantity": 0,
    "stopPrice": 0,
    "price": 0,
    "workingType": "",
    "stopGuaranteed": "false"
  },
  "stopLoss": {
    "type": "STOP",
    "quantity": 0,
    "stopPrice": 0,
    "price": 0,
    "workingType": "",
    "stopGuaranteed": "false"
  },
  "advanceAttr": 0,
  "positionID": 2077110178940981248,
  "takeProfitEntrustPrice": 0,
  "stopLossEntrustPrice": 0,
  "orderType": "",
  "workingType": "MARK_PRICE",
  "onlyOnePosition": true,
  "reduceOnly": false,
  "postOnly": false,
  "stopGuaranteed": "false",
  "triggerOrderId": 0,
  "trailingStopRate": 0,
  "trailingStopDistance": 0,
  "is_twap": false,
  "mainOrderId": "",
  "priceRate": "",
  "actPrice": "",
  "closePosition": "false"
}
```