diff --git a/modules/nf-core/umicollapse/main.nf b/modules/nf-core/umicollapse/main.nf
index 314e0df1..fdecd6d9 100644
--- a/modules/nf-core/umicollapse/main.nf
+++ b/modules/nf-core/umicollapse/main.nf
@@ -26,6 +26,7 @@ process UMICOLLAPSE {
     """
     umicollapse \\
         -Xmx${(task.memory.toMega() * 0.8).intValue()}M \\
+        -Xss99M \\
         bam \\
         -i $bam \\
         -o ${prefix}.bam \\