diff --git a/chain/messagepool/pruning.go b/chain/messagepool/pruning.go
index 11719049d..a4dce3e6d 100644
--- a/chain/messagepool/pruning.go
+++ b/chain/messagepool/pruning.go
@@ -44,7 +44,7 @@ func (mp *MessagePool) pruneMessages(ctx context.Context, ts *types.TipSet) erro
 	}
 
 	// Sort the chains
-	sort.Slice(chains, func(i, j int) bool {
+	sort.SliceStable(chains, func(i, j int) bool {
 		return chains[i].Before(chains[j])
 	})
 
diff --git a/chain/messagepool/selection.go b/chain/messagepool/selection.go
index e2cc797b9..e14efe8d1 100644
--- a/chain/messagepool/selection.go
+++ b/chain/messagepool/selection.go
@@ -60,7 +60,7 @@ func (mp *MessagePool) selectMessages(curTs, ts *types.TipSet) ([]*types.SignedM
 	}
 
 	// 2. Sort the chains
-	sort.Slice(chains, func(i, j int) bool {
+	sort.SliceStable(chains, func(i, j int) bool {
 		return chains[i].Before(chains[j])
 	})