diff --git a/functions/src/scripts/migrate-to-dpm-2.ts b/functions/src/scripts/migrate-to-dpm-2.ts
new file mode 100644
index 00000000..058f510a
--- /dev/null
+++ b/functions/src/scripts/migrate-to-dpm-2.ts
@@ -0,0 +1,71 @@
+import * as admin from 'firebase-admin'
+
+import { Contract } from '../../../common/contract'
+
+type DocRef = admin.firestore.DocumentReference
+
+// Generate your own private key, and set the path below:
+// https://console.firebase.google.com/u/0/project/mantic-markets/settings/serviceaccounts/adminsdk
+// const serviceAccount = require('../../../../../../Downloads/dev-mantic-markets-firebase-adminsdk-sir5m-b2d27f8970.json')
+const serviceAccount = require('../../../../../../Downloads/mantic-markets-firebase-adminsdk-1ep46-820891bb87.json')
+
+admin.initializeApp({
+  credential: admin.credential.cert(serviceAccount),
+})
+const firestore = admin.firestore()
+
+async function recalculateContract(contractRef: DocRef, contract: Contract) {
+  const startPool = (contract as any).startPool as
+    | undefined
+    | { YES: number; NO: number }
+
+  if (contract.phantomShares || !startPool) return
+
+  const phantomAnte = startPool.YES + startPool.NO
+  const p = startPool.YES ** 2 / (startPool.YES ** 2 + startPool.NO ** 2)
+
+  const phantomShares = {
+    YES: Math.sqrt(p) * phantomAnte,
+    NO: Math.sqrt(1 - p) * phantomAnte,
+  }
+
+  const pool = {
+    YES: contract.pool.YES - startPool.YES,
+    NO: contract.pool.NO - startPool.NO,
+  }
+
+  const totalShares = {
+    YES: contract.totalShares.YES + phantomShares.YES,
+    NO: contract.totalShares.NO + phantomShares.NO,
+  }
+
+  const update: Partial<Contract> = {
+    mechanism: 'dpm-2',
+    phantomShares,
+    pool,
+    totalShares,
+  }
+
+  await contractRef.update(update)
+
+  console.log('updated', contract.slug, 'with', update)
+  console.log()
+}
+
+async function recalculateContractTotals() {
+  console.log('Migrating ante calculations to DPM-2')
+
+  const snapshot = await firestore.collection('contracts').get()
+  const contracts = snapshot.docs.map((doc) => doc.data() as Contract)
+
+  console.log('Loaded', contracts.length, 'contracts')
+
+  for (const contract of contracts) {
+    const contractRef = firestore.doc(`contracts/${contract.id}`)
+
+    await recalculateContract(contractRef, contract)
+  }
+}
+
+if (require.main === module)
+  recalculateContractTotals().then(() => process.exit())