diff --git a/functions/src/scripts/backfill-fees.ts b/functions/src/scripts/backfill-fees.ts
new file mode 100644
index 00000000..9ca068d2
--- /dev/null
+++ b/functions/src/scripts/backfill-fees.ts
@@ -0,0 +1,25 @@
+// We have many old contracts without a collectedFees data structure. Let's fill them in.
+
+import * as admin from 'firebase-admin'
+import { initAdmin } from './script-init'
+import { noFees } from '../../../common/fees'
+
+initAdmin()
+const firestore = admin.firestore()
+
+if (require.main === module) {
+  const contractsRef = firestore.collection('contracts')
+  contractsRef.get().then((contractsSnaps) => {
+    let n = 0
+    console.log(`Loaded ${contractsSnaps.size} contracts.`)
+    contractsSnaps.forEach((ct) => {
+      const data = ct.data()
+      if (!('collectedFees' in data)) {
+        n += 1
+        console.log(`Filling in missing fees on contract ${data.id}...`)
+        ct.ref.update({ collectedFees: noFees })
+      }
+    })
+    console.log(`Updated ${n} contracts.`)
+  })
+}