diff --git a/docs/evidence/interned-stock-state-symbols-20260905.json b/docs/evidence/interned-stock-state-symbols-20260905.json
new file mode 100644
index 0000000..b9e0570
--- /dev/null
+++ b/docs/evidence/interned-stock-state-symbols-20260905.json
@@ -0,0 +1,95 @@
+{
+  "schemaVersion": "fidc-interned-stock-state-symbols/v1",
+  "measuredAt": "2026-09-05T01:50:00+08:00",
+  "host": "192.168.31.177",
+  "engineCommit": "e5646ef80c9a5c6d2d3a1b9b6f330fbbc27aa4ab",
+  "runnerBinarySha256": "c2f6f0b8cc194a5e3f668bcc0d54b3712cf037267ccc6c04d5f850d8ccbd6314",
+  "implementation": {
+    "description": "intern each canonical symbol once in DataSet and clone Arc<str> into per-date StockExpressionState objects instead of allocating a String for every state",
+    "rhaiStringBoundaryPreserved": true,
+    "crossDateSharedSymbolTested": true,
+    "cachedFactorValues": false,
+    "cachedSelectionResults": false,
+    "pitSemanticsChanged": false
+  },
+  "primaryFiveYearContract": {
+    "startDate": "2021-08-23",
+    "endDate": "2026-08-28",
+    "frequency": "1d",
+    "matchingType": "next_bar_open",
+    "totalReturn": 0.9219861819172002,
+    "tradeCount": 26088,
+    "canonicalSha256": "b42fea66237d06eadb24f6b8c9e2760e7319fe3699f315b99e01f433ef2aa234",
+    "resultStoreSha256": "92343fb369fea68b2544b654151c5c43a935940580b14afbe8eefb3844f72a54",
+    "lowContentionEngineSeconds": [5.505, 5.748, 5.67, 6.005, 6.497],
+    "medianEngineSeconds": 5.748,
+    "compactKeyBaselineMedianEngineSeconds": 5.734,
+    "resultConsistent": true,
+    "terminalAuditStatus": "clean"
+  },
+  "secondaryFiveYearContract": {
+    "totalReturn": 1.1342962298106998,
+    "tradeCount": 19404,
+    "canonicalSha256": "0dbd3fad624097c673c4a5ec2f545f95e9c21d1d5337bb2b48ffeb22b16cb2b9",
+    "resultStoreSha256": "416d2f87241fb4c6b917f6aeecb588f82f6e7d51a103f4c53a74d11971f16839",
+    "engineSeconds": [5.648, 5.35, 5.003],
+    "medianEngineSeconds": 5.35,
+    "resultConsistent": true,
+    "terminalAuditStatus": "clean"
+  },
+  "hardwareCounters": {
+    "candidateRunId": "btr_1788544043073_3041540_6",
+    "candidateEngineSeconds": 8.227,
+    "candidateInstructions": 27997441984,
+    "candidateBranches": 4947191270,
+    "earlierSharedIndexBaselineInstructions": 28218847364,
+    "earlierSharedIndexBaselineBranches": 5024236708,
+    "observedInstructionReductionPercent": 0.7846044523842924,
+    "observedBranchReductionPercent": 1.533451728719079,
+    "attributionNote": "the earlier hardware baseline predates the compact cache-key change, so counters prove the combined structural reduction rather than symbol interning alone"
+  },
+  "profile": {
+    "runId": "btr_1788544253262_3041540_15",
+    "totalSeconds": 6.136,
+    "engineSeconds": 5.509,
+    "eventCycles": 15296376746,
+    "stockStatePercent": 16.25,
+    "preInternStockStatePercent": 23.86,
+    "mallocPercent": 4.22,
+    "numericVmPercent": 6.02,
+    "adjustedCloseMovingAveragePercent": 5.10
+  },
+  "excludedHighContentionBatch": {
+    "hostLoadAveragePeak": 69.23,
+    "engineSeconds": [7.247, 7.094, 7.481, 7.967, 37.981, 44.366],
+    "resultConsistent": true,
+    "performanceComparisonExcluded": true,
+    "reason": "independent tan child processes executed on backtest-reserved CPUs; no external process was modified"
+  },
+  "memory": {
+    "serviceCgroupCurrentBytes": 11485425664,
+    "serviceCgroupPeakBytes": 11488174080,
+    "processRssKiB": 11196756,
+    "processAnonymousKiB": 11180328
+  },
+  "testGate": {
+    "coreUnitTotal": 420,
+    "corePassed": 414,
+    "ignoredManualBenchmarks": 6,
+    "failed": 0,
+    "integrationSuitesPassed": true
+  },
+  "remoteArtifacts": [
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-20260905.json",
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-low-contention-20260905.json",
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-secondary-20260905.json",
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-perf-stat-20260905/perf-stat.csv",
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-profile-20260905/perf.data",
+    "/srv/fidc/canonical/run/fidc-private/evidence/interned-stock-symbol-profile-20260905/perf-report.txt"
+  ],
+  "acceptance": {
+    "status": "accepted_structural_allocation_reduction_no_regression",
+    "endToEndSpeedupClaimed": false,
+    "reason": "both five-year strategies preserve exact outputs, low-contention wall time is neutral, and the stock-state profile plus hardware counters show less allocation-related work"
+  }
+}