diff --git a/factorize.m b/factorize.m
index ee801cddee41877b29848445543b999c9e5b4b9a..447434be4457f55145c42c631881dc9ab9e97075 100644
--- a/factorize.m
+++ b/factorize.m
@@ -6,6 +6,8 @@ Mask = isnan(M);
 M(Mask) = 0;
 
 [U,S,V] = utils.svd_nsq(M);
+U = -U;
+V = -V;
 B = U(:,1:k)*S(1:k,1:k);
 C = V(:,1:k)';