diff --git a/src/zm_comms.h b/src/zm_comms.h
index 070ed5395..ce316b17b 100644
--- a/src/zm_comms.h
+++ b/src/zm_comms.h
@@ -244,6 +244,7 @@ class Socket : public CommsBase {
   }
 
   virtual ssize_t recv(std::string &msg) const {
+    msg.reserve(ZM_NETWORK_BUFSIZ);
     std::vector<char> buffer(msg.capacity());
     ssize_t nBytes;
     if ((nBytes = ::recv(mSd, buffer.data(), buffer.size(), 0)) < 0) {