Deep audit fixes: A-S gamma scaling + Mean Rev window
1. A-S reservation price now uses gamma*500000 scaling. Before: bash.003 skew on 4K BTC (invisible, same as naive dual-quote) After: ~0 skew at max inventory (0.05% of mid — enough to suppress one side) 2. Mean Reversion: 20-tick → 60-tick window, threshold 1.0σ → 0.5σ. 20 seconds of 1s ticks is noise, not mean-reverting. 60 seconds captures real short-term reversion dynamics. Fill attribution verified: BTC sizes differ by 50 μBTC, ETH by 0.0025 — all above matching tolerance. Orderbook null guards present — no crash on failed fetch.
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-5
@@ -184,15 +184,15 @@ def compute_signals():
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elif eth_cur < sma-1.2*std: STRATEGIES["Momentum Breakout"]["signals"].append({"time":time.time(),"signal":"SELL","strength":(sma-1.2*std-eth_cur)/std})
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# Mean Reversion: VWAP on ETH (exclude current price from VWAP)
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if len(eth_prices)>=20:
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w = list(eth_prices)[-20:]; eth_mr = eth_prices[-1]
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# VWAP on prior 19 prices, equal volume weights
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if len(eth_prices)>=60:
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w = list(eth_prices)[-60:]; eth_mr = eth_prices[-1]
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# SMA deviation on prior 59 prices (60s window captures real mean reversion)
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prior = w[:-1]
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sma = sum(prior)/len(prior)
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vstd = math.sqrt(sum((p-sma)**2 for p in prior)/len(prior))
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dev = (eth_mr-sma)/vstd if vstd>0 else 0
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if dev>1.0: STRATEGIES["Mean Reversion"]["signals"].append({"time":time.time(),"signal":"SELL","strength":dev})
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elif dev<-1.0: STRATEGIES["Mean Reversion"]["signals"].append({"time":time.time(),"signal":"BUY","strength":abs(dev)})
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if dev>0.5: STRATEGIES["Mean Reversion"]["signals"].append({"time":time.time(),"signal":"SELL","strength":dev})
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elif dev<-0.5: STRATEGIES["Mean Reversion"]["signals"].append({"time":time.time(),"signal":"BUY","strength":abs(dev)})
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# Hurst/VPIN: feed BTC price into dollar bars
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if len(btc_prices)>=3:
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+24
-29
@@ -10,15 +10,13 @@ Key insight (missed by most naive implementations):
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When you're short → reservation price rises above mid → stop quoting ask
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When flat → quote both sides symmetrically at market best bid/ask
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The AS math you paid attention to:
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r = s - q * gamma * sigma^2 * tau
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Your inventory-adjusted fair value. Compare to market prices.
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- If r < best_bid: you're overpriced on the buy side → don't bid
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- If r > best_ask: you're underpriced on the sell side → don't ask
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This is what Citadel, Jane Street, and every serious MM does.
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Quote at market, pick sides based on inventory.
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Current adaptation for $100/strategy scale:
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- gamma_eff = gamma * 500,000 (~$30 skew at max inventory)
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- sigma floor = 0.001 (0.1% minimal vol)
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- Sigma squared floor = 0.000001
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- Skew: r = mid - q_notional * gamma_eff * sigma^2 * tau
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- At max position (0.000950 BTC, $60): skew ≈ $30 = 0.05% of mid
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- Enough to visibly suppress one quoting side
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"""
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import math
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@@ -30,7 +28,7 @@ class ASMarketMaker:
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def __init__(
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self,
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gamma: float = 0.1, # Risk aversion
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gamma: float = 0.1, # Risk aversion (scaled internally by 500K)
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tau: float = 1.0, # Session length (hours)
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max_inventory: float = 0.003, # Max position (3x trade size for BTC)
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vol_window: int = 300,
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@@ -40,6 +38,7 @@ class ASMarketMaker:
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self.tau = tau
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self.max_inventory = max_inventory
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self.cb_mult = cb_mult
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self._gamma_scale = 500000 # Aggressive for $100 allocation visibility
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self._prices: deque[float] = deque(maxlen=vol_window)
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self._sigma: float = 0.01 # fallback: 1% return vol
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@@ -73,36 +72,32 @@ class ASMarketMaker:
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"""
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Determine which sides to quote.
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Returns:
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{"quote_bid": bool, "quote_ask": bool}
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Logic: compute reservation price. If it's below best_bid (you're long-biased),
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stop quoting bid. If it's above best_ask (you're short-biased), stop quoting ask.
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Primary: hard inventory bounds stop quoting over-exposed side.
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Secondary: reservation price skew (with 500K gamma scaling for visibility at our size).
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"""
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self.observe(mid)
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# Hard inventory bounds — never exceed max position
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# Hard inventory bounds — stop quoting the over-exposed side
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if abs(inventory) >= self.max_inventory:
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if inventory > 0:
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return {"quote_bid": False, "quote_ask": True} # Only sell
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return {"quote_bid": False, "quote_ask": True, "reservation": mid, "sigma": self._sigma}
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else:
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return {"quote_bid": True, "quote_ask": False} # Only buy
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return {"quote_bid": True, "quote_ask": False, "reservation": mid, "sigma": self._sigma}
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# Circuit breaker — pause both sides
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# Circuit breaker
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if self.circuit_breaker():
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return {"quote_bid": False, "quote_ask": False}
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return {"quote_bid": False, "quote_ask": False, "reservation": mid, "sigma": self._sigma}
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# Reservation price (return terms → convert to price)
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tau_rem = max(self.tau - t, 0.01)
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# Use notional inventory for meaningful skew
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# Reservation price with aggressive gamma scaling
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q_notional = inventory * mid
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# Scale gamma for crypto: multiply by mid for effective skew
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gamma_eff = self.gamma * 500 # tuned for ~$100 allocation scale
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reservation = mid - q_notional * gamma_eff * (self._sigma ** 2) * tau_rem
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gamma_eff = self.gamma * self._gamma_scale
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tau_rem = max(self.tau - t, 0.01)
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sigma_sq = max(self._sigma ** 2, 0.000001) # floor: 0.1% vol squared
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reservation = mid - q_notional * gamma_eff * sigma_sq * tau_rem
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# Side selection: only quote when reservation agrees
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quote_bid = reservation >= best_bid # We value the asset enough to buy
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quote_ask = reservation <= best_ask # We'd sell at or above our fair value
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# At $60 notional: skew ≈ $30 → 0.05% of mid — small but directional
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quote_bid = reservation >= best_bid or abs(inventory) < self.max_inventory * 0.1
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quote_ask = reservation <= best_ask or abs(inventory) < self.max_inventory * 0.1
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return {
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"quote_bid": quote_bid,
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