diff --git a/.env.example b/.env.example
index 36bc452..a589881 100644
--- a/.env.example
+++ b/.env.example
@@ -67,3 +67,6 @@ CLASSIFIER_SPIKE_MIN_SIZE_Z=2
 CLASSIFIER_Z_MIN_SAMPLES=12
 CLASSIFIER_MIN_NBBO_COVERAGE=0.5
 CLASSIFIER_MIN_AGGRESSOR_RATIO=0.55
+CLASSIFIER_0DTE_MAX_ATM_PCT=0.01
+CLASSIFIER_0DTE_MIN_PREMIUM=20000
+CLASSIFIER_0DTE_MIN_SIZE=400
diff --git a/README.md b/README.md
index d163311..56597bc 100644
--- a/README.md
+++ b/README.md
@@ -196,6 +196,9 @@ Provider links: [Interactive Brokers](https://www.interactivebrokers.com/), [IBK
 - `CLASSIFIER_Z_MIN_SAMPLES` (default `12`) — minimum samples before z-scores apply.  
 - `CLASSIFIER_MIN_NBBO_COVERAGE` (default `0.5`) — NBBO coverage ratio gate.  
 - `CLASSIFIER_MIN_AGGRESSOR_RATIO` (default `0.55`) — aggressor ratio gate.  
+- `CLASSIFIER_0DTE_MAX_ATM_PCT` (default `0.01`) — max ATM distance as pct of underlying for 0DTE gamma punch.  
+- `CLASSIFIER_0DTE_MIN_PREMIUM` (default `20000`) — 0DTE gamma punch premium floor.  
+- `CLASSIFIER_0DTE_MIN_SIZE` (default `400`) — 0DTE gamma punch size floor.  
 
 ### Testing + throttling
 
diff --git a/services/compute/src/classifiers.ts b/services/compute/src/classifiers.ts
index 824886e..3eef846 100644
--- a/services/compute/src/classifiers.ts
+++ b/services/compute/src/classifiers.ts
@@ -12,6 +12,9 @@ export type ClassifierConfig = {
   zMinSamples: number;
   minNbboCoverage: number;
   minAggressorRatio: number;
+  zeroDteMaxAtmPct: number;
+  zeroDteMinPremium: number;
+  zeroDteMinSize: number;
 };
 
 const MS_PER_DAY = 86_400_000;
@@ -42,6 +45,13 @@ const getStringFeature = (packet: FlowPacket, key: string): string => {
 
 const formatPct = (value: number): string => `${Math.round(value * 100)}%`;
 
+const formatPctPrecise = (value: number, digits = 2): string => {
+  if (!Number.isFinite(value)) {
+    return "0%";
+  }
+  return `${(value * 100).toFixed(digits)}%`;
+};
+
 const getAggressorContext = (
   packet: FlowPacket
 ): {
@@ -183,6 +193,14 @@ const getReferenceTs = (packet: FlowPacket): number | null => {
   return null;
 };
 
+const getReferenceDay = (packet: FlowPacket): string | null => {
+  const referenceTs = getReferenceTs(packet);
+  if (!referenceTs) {
+    return null;
+  }
+  return new Date(referenceTs).toISOString().slice(0, 10);
+};
+
 const getDteDays = (packet: FlowPacket, contract: ParsedContract): number | null => {
   const expiryTs = Date.parse(`${contract.expiry}T00:00:00Z`);
   if (!Number.isFinite(expiryTs)) {
@@ -666,6 +684,67 @@ const buildFarDatedHit = (
   };
 };
 
+const buildZeroDteGammaPunchHit = (
+  packet: FlowPacket,
+  contract: ParsedContract,
+  config: ClassifierConfig
+): ClassifierHit | null => {
+  const referenceDay = getReferenceDay(packet);
+  if (!referenceDay || contract.expiry !== referenceDay) {
+    return null;
+  }
+
+  const activity = getLargeActivity(packet, config);
+  if (
+    activity.totalPremium < config.zeroDteMinPremium ||
+    activity.totalSize < config.zeroDteMinSize
+  ) {
+    return null;
+  }
+
+  const underlyingMid = getNumberFeature(packet, "underlying_mid");
+  if (!Number.isFinite(underlyingMid) || underlyingMid <= 0) {
+    return null;
+  }
+
+  const strike = contract.strike;
+  const atmPct = Math.abs(strike - underlyingMid) / underlyingMid;
+  if (atmPct > config.zeroDteMaxAtmPct) {
+    return null;
+  }
+
+  const { coverage, aggressiveRatio } = getAggressorContext(packet);
+  let confidence = 0.55;
+  if (atmPct <= config.zeroDteMaxAtmPct * 0.5) {
+    confidence += 0.05;
+  }
+  if (activity.totalPremium >= config.zeroDteMinPremium * 2) {
+    confidence += 0.1;
+  }
+  if (activity.totalSize >= config.zeroDteMinSize * 2) {
+    confidence += 0.05;
+  }
+
+  const aggressor = applyAggressorAdjustment(confidence, coverage, aggressiveRatio, config);
+  confidence = clamp(aggressor.confidence, 0, 0.9);
+
+  return {
+    classifier_id: "zero_dte_gamma_punch",
+    confidence,
+    direction: contract.right === "C" ? "bullish" : "bearish",
+    explanations: [
+      `Likely 0DTE gamma punch: ${packet.features.option_contract_id ?? packet.id} near ATM.`,
+      `Underlying mid ${formatUsd(underlyingMid)}, strike ${formatUsd(strike)} (${formatPctPrecise(atmPct)} from ATM).`,
+      `Premium ${formatUsd(activity.totalPremium)} across ${Math.round(activity.totalSize)} contracts.`,
+      `Thresholds: DTE=0, ATM <=${formatPctPrecise(config.zeroDteMaxAtmPct)}, >=${formatUsd(
+        config.zeroDteMinPremium
+      )} premium, >=${config.zeroDteMinSize} contracts.`,
+      activity.baselineNote,
+      aggressor.note
+    ]
+  };
+};
+
 export const evaluateClassifiers = (
   packet: FlowPacket,
   config: ClassifierConfig
@@ -710,6 +789,11 @@ export const evaluateClassifiers = (
     if (farDatedHit) {
       hits.push(farDatedHit);
     }
+
+    const zeroDteHit = buildZeroDteGammaPunchHit(packet, contract, config);
+    if (zeroDteHit) {
+      hits.push(zeroDteHit);
+    }
   }
 
   const structureHit = buildStraddleStrangleHit(packet, config);
diff --git a/services/compute/src/index.ts b/services/compute/src/index.ts
index 042e6df..315c65f 100644
--- a/services/compute/src/index.ts
+++ b/services/compute/src/index.ts
@@ -115,7 +115,10 @@ const envSchema = z.object({
   CLASSIFIER_SPIKE_MIN_SIZE_Z: z.coerce.number().nonnegative().default(2),
   CLASSIFIER_Z_MIN_SAMPLES: z.coerce.number().int().nonnegative().default(12),
   CLASSIFIER_MIN_NBBO_COVERAGE: z.coerce.number().min(0).max(1).default(0.5),
-  CLASSIFIER_MIN_AGGRESSOR_RATIO: z.coerce.number().min(0).max(1).default(0.55)
+  CLASSIFIER_MIN_AGGRESSOR_RATIO: z.coerce.number().min(0).max(1).default(0.55),
+  CLASSIFIER_0DTE_MAX_ATM_PCT: z.coerce.number().min(0).max(1).default(0.01),
+  CLASSIFIER_0DTE_MIN_PREMIUM: z.coerce.number().positive().default(20_000),
+  CLASSIFIER_0DTE_MIN_SIZE: z.coerce.number().int().positive().default(400)
 });
 
 const env = readEnv(envSchema);
@@ -130,7 +133,10 @@ const classifierConfig: ClassifierConfig = {
   spikeMinSizeZ: env.CLASSIFIER_SPIKE_MIN_SIZE_Z,
   zMinSamples: env.CLASSIFIER_Z_MIN_SAMPLES,
   minNbboCoverage: env.CLASSIFIER_MIN_NBBO_COVERAGE,
-  minAggressorRatio: env.CLASSIFIER_MIN_AGGRESSOR_RATIO
+  minAggressorRatio: env.CLASSIFIER_MIN_AGGRESSOR_RATIO,
+  zeroDteMaxAtmPct: env.CLASSIFIER_0DTE_MAX_ATM_PCT,
+  zeroDteMinPremium: env.CLASSIFIER_0DTE_MIN_PREMIUM,
+  zeroDteMinSize: env.CLASSIFIER_0DTE_MIN_SIZE
 };
 
 const darkInferenceConfig: DarkInferenceConfig = {
@@ -485,6 +491,34 @@ const flushCluster = async (
     window_ms: env.CLUSTER_WINDOW_MS
   };
 
+  const parsedContract = parseContractId(cluster.contractId);
+  if (parsedContract?.root) {
+    features.underlying_id = parsedContract.root;
+    const quoteJoin = selectEquityQuote(parsedContract.root, cluster.endTs);
+    if (!quoteJoin.quote) {
+      joinQuality.underlying_quote_missing = 1;
+    } else {
+      joinQuality.underlying_quote_age_ms = quoteJoin.ageMs;
+      if (quoteJoin.stale) {
+        joinQuality.underlying_quote_stale = 1;
+      } else {
+        const bid = quoteJoin.quote.bid;
+        const ask = quoteJoin.quote.ask;
+        if (Number.isFinite(bid) && Number.isFinite(ask) && ask > 0) {
+          const mid = (bid + ask) / 2;
+          const spread = ask - bid;
+          features.underlying_quote_ts = quoteJoin.quote.ts;
+          features.underlying_bid = bid;
+          features.underlying_ask = ask;
+          features.underlying_mid = roundTo(mid);
+          features.underlying_spread = roundTo(spread);
+        } else {
+          joinQuality.underlying_quote_missing = 1;
+        }
+      }
+    }
+  }
+
   const placementTotal =
     cluster.placements.aa +
     cluster.placements.a +
diff --git a/services/compute/tests/classifiers.test.ts b/services/compute/tests/classifiers.test.ts
index 81aece7..ab3b110 100644
--- a/services/compute/tests/classifiers.test.ts
+++ b/services/compute/tests/classifiers.test.ts
@@ -12,7 +12,10 @@ const baseConfig: ClassifierConfig = {
   spikeMinSizeZ: 2,
   zMinSamples: 12,
   minNbboCoverage: 0.5,
-  minAggressorRatio: 0.55
+  minAggressorRatio: 0.55,
+  zeroDteMaxAtmPct: 0.01,
+  zeroDteMinPremium: 20_000,
+  zeroDteMinSize: 400
 };
 
 const DEFAULT_TS = Date.UTC(2024, 0, 2);
@@ -187,4 +190,19 @@ describe("classifier structure and positioning signals", () => {
     const hit = hits.find((candidate) => candidate.classifier_id === "far_dated_conviction");
     expect(hit?.direction).toBe("bullish");
   });
+
+  test("zero dte gamma punch triggers when ATM and large", () => {
+    const packet = buildPacket({
+      option_contract_id: "SPY-2024-01-02-450-C",
+      total_premium: 35_000,
+      total_size: 600,
+      underlying_mid: 450,
+      nbbo_coverage_ratio: 0.8,
+      nbbo_aggressive_buy_ratio: 0.7,
+      nbbo_aggressive_sell_ratio: 0.3
+    });
+    const hits = evaluateClassifiers(packet, baseConfig);
+    const hit = hits.find((candidate) => candidate.classifier_id === "zero_dte_gamma_punch");
+    expect(hit?.direction).toBe("bullish");
+  });
 });