diff --git a/include/runtime_services/ffa_helpers.h b/include/runtime_services/ffa_helpers.h
index 766ea39..c68a014 100644
--- a/include/runtime_services/ffa_helpers.h
+++ b/include/runtime_services/ffa_helpers.h
@@ -236,6 +236,9 @@
 #define FFA_MEMORY_REGION_TRANSACTION_TYPE_LEND ((0x2U) << 3)
 #define FFA_MEMORY_REGION_TRANSACTION_TYPE_DONATE ((0x3U) << 3)
 
+/** The maximum number of recipients a memory region may be sent to. */
+#define MAX_MEM_SHARE_RECIPIENTS 1U
+
 /**
  * This corresponds to table "Endpoint memory access descriptor" of the FFA 1.0
  * specification.