diff --git a/lib/cash-out/cash-out-atomic.js b/lib/cash-out/cash-out-atomic.js
index b03d51f5..3066dca4 100644
--- a/lib/cash-out/cash-out-atomic.js
+++ b/lib/cash-out/cash-out-atomic.js
@@ -19,7 +19,8 @@ function atomic (tx, pi, fromClient) {
   const isolationLevel = pgp.txMode.isolationLevel
   const mode = new TransactionMode({ tiLevel: isolationLevel.serializable })
   function transaction (t) {
-    const sql = 'select * from cash_out_txs where id=$1'
+    const sql = 'SELECT * FROM cash_out_txs WHERE id=$1 FOR UPDATE'
+
     return t.oneOrNone(sql, [tx.id])
       .then(toObj)
       .then(oldTx => {