diff --git a/api/db/migrations/20240924091540_add-reconciliation-date-to-former-candidates.js b/api/db/migrations/20240924091540_add-reconciliation-date-to-former-candidates.js
new file mode 100644
index 00000000000..dbd433a90ca
--- /dev/null
+++ b/api/db/migrations/20240924091540_add-reconciliation-date-to-former-candidates.js
@@ -0,0 +1,45 @@
+import { logger } from '../../src/shared/infrastructure/utils/logger.js';
+
+const TABLE_NAME = 'certification-candidates';
+
+const up = async function (knex) {
+  let numberOfBatchProcessed = 0;
+  const CHUNK_SIZE = 250000;
+
+  let hasNext = false;
+  do {
+    const updates = await knex.raw(
+      `
+update "certification-candidates"
+set "reconciledAt" = "subquery"."reconciledAt"
+from (select
+  "certification-candidates"."id" as "id",
+  "certification-courses"."createdAt" as "reconciledAt"
+  from "certification-candidates"
+  left join "certification-courses" on "certification-courses"."userId" = "certification-candidates"."userId"
+  and "certification-courses"."sessionId" = "certification-candidates"."sessionId"
+  where "certification-candidates"."userId" is not null
+  and "certification-candidates"."reconciledAt" is null
+  limit ?) as "subquery"
+ where "certification-candidates"."id" = "subquery"."id"
+ returning "certification-candidates"."id", "certification-candidates"."reconciledAt";`,
+      [CHUNK_SIZE],
+    );
+
+    hasNext = updates.rowCount === CHUNK_SIZE;
+    ++numberOfBatchProcessed;
+    logger.info(
+      `${TABLE_NAME}: Batch number ${numberOfBatchProcessed} : ${updates.rowCount} items updated. hasNext = ${hasNext}`,
+    );
+  } while (hasNext);
+};
+
+const down = async function (knex) {
+  return knex(TABLE_NAME).update('reconciledAt', null);
+};
+
+// We UPDATE in batch of CHUNK_SIZE, hence not needing a transaction for this migration
+// @see: https://knexjs.org/guide/migrations.html#migration-api
+const config = { transaction: false };
+
+export { config, down, up };