diff --git a/hub/db/db.py b/hub/db/db.py
index 5f289b7..69806d1 100644
--- a/hub/db/db.py
+++ b/hub/db/db.py
@@ -34,7 +34,7 @@ NAMESPACE = f"{PROMETHEUS_NAMESPACE}_db"
 
 
 class SecondaryDB:
-    DB_VERSIONS = [7, 8, 9, 10, 11]
+    DB_VERSIONS = [7, 8, 9, 10, 11, 12]
 
     def __init__(self, coin, db_dir: str, secondary_name: str, max_open_files: int = -1, reorg_limit: int = 200,
                  cache_all_claim_txos: bool = False, cache_all_tx_hashes: bool = False,
diff --git a/hub/db/migrators/migrate11to12.py b/hub/db/migrators/migrate11to12.py
new file mode 100644
index 0000000..d76c795
--- /dev/null
+++ b/hub/db/migrators/migrate11to12.py
@@ -0,0 +1,57 @@
+import logging
+from collections import defaultdict
+
+FROM_VERSION = 11
+TO_VERSION = 12
+
+
+def migrate(db):
+    log = logging.getLogger(__name__)
+    prefix_db = db.prefix_db
+
+    log.info("migrating the db to version 12")
+
+    effective_amounts = defaultdict(int)
+
+    log.info("deleting any existing future effective amounts")
+
+    to_delete = list(prefix_db.future_effective_amount.iterate(deserialize_key=False, deserialize_value=False))
+    while to_delete:
+        batch, to_delete = to_delete[:100000], to_delete[100000:]
+        if batch:
+            prefix_db.multi_delete(batch)
+            prefix_db.unsafe_commit()
+
+    log.info("calculating future claim effective amounts for the new index at block %i", db.db_height)
+    cnt = 0
+    for k, v in prefix_db.active_amount.iterate():
+        cnt += 1
+        effective_amounts[k.claim_hash] += v.amount
+        if cnt % 1000000 == 0:
+            log.info("scanned %i amounts for %i claims", cnt, len(effective_amounts))
+    log.info("preparing to insert future effective amounts")
+
+    effective_amounts_to_put = [
+        prefix_db.future_effective_amount.pack_item(claim_hash, effective_amount)
+        for claim_hash, effective_amount in effective_amounts.items()
+    ]
+
+    log.info("inserting %i future effective amounts", len(effective_amounts_to_put))
+
+    cnt = 0
+
+    while effective_amounts_to_put:
+        batch, effective_amounts_to_put = effective_amounts_to_put[:100000], effective_amounts_to_put[100000:]
+        if batch:
+            prefix_db.multi_put(batch)
+            prefix_db.unsafe_commit()
+            cnt += len(batch)
+            if cnt % 1000000 == 0:
+                log.info("inserted effective amounts for %i claims", cnt)
+
+    log.info("finished building the effective amount index")
+
+    db.db_version = 12
+    db.write_db_state()
+    db.prefix_db.unsafe_commit()
+    log.info("finished migration to version 12")
diff --git a/hub/scribe/service.py b/hub/scribe/service.py
index 9c3561d..abe537d 100644
--- a/hub/scribe/service.py
+++ b/hub/scribe/service.py
@@ -2145,6 +2145,9 @@ class BlockchainProcessorService(BlockchainService):
             elif self.db.db_version == 10:
                 from hub.db.migrators.migrate10to11 import migrate, FROM_VERSION, TO_VERSION
                 self.db._index_address_status = self.env.index_address_status
+            elif self.db.db_version == 11:
+                from hub.db.migrators.migrate11to12 import migrate, FROM_VERSION, TO_VERSION
+                self.db._index_address_status = self.env.index_address_status
             else:
                 raise RuntimeError("unknown db version")
             self.log.warning(f"migrating database from version {FROM_VERSION} to version {TO_VERSION}")