diff --git a/common.ant.xml b/common.ant.xml
index ea0d870..845d205 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -210,7 +210,7 @@
       <junit dir="@{test.out}" fork="yes" printsummary="yes"
              failureproperty="junit.failure" tempdir="@{test.out}">
         <jvmarg line="-Xmx768m" />
-        <jvmarg line="-Xss512k" />
+        <jvmarg line="-Xss4M" />
         <jvmarg value="-Demma.coverage.out.file=@{test.emma.coverage}/coverage.emma" />
         <jvmarg value="-Demma.coverage.out.merge=true" />
         <jvmarg value="-Dcom.google.gwt.junit.reportPath=reports" />