diff --git a/python/templates/SIOBlock.cc.jinja2 b/python/templates/SIOBlock.cc.jinja2
index 0ed56ef45..f8090ea75 100644
--- a/python/templates/SIOBlock.cc.jinja2
+++ b/python/templates/SIOBlock.cc.jinja2
@@ -25,8 +25,8 @@ void {{ block_class }}::read(sio::read_device& device, sio::version_type version
   if (not m_subsetColl) {
     unsigned size(0);
     device.data( size );
-    m_buffers.data = new std::vector<{{ class.full_type }}Data>(size);
     auto* dataVec = m_buffers.dataAsVector<{{ class.full_type }}Data>();
+    dataVec->resize(size);
     podio::handlePODDataSIO(device, dataVec->data(), size);
   }