diff --git a/roaring/container_stash.go b/roaring/container_stash.go
index 8aab2f4d3..89c63ac8f 100644
--- a/roaring/container_stash.go
+++ b/roaring/container_stash.go
@@ -428,6 +428,9 @@ func (c *Container) AsBitmap(target []uint64) (out []uint64) {
 		out = make([]uint64, 1024)
 	} else {
 		out = target
+		for i := range out {
+			out[i] = 0
+		}
 	}
 	if c.typeID == containerArray {
 		a := c.array()