diff --git a/include/commodity.h b/include/commodity.h
index cba8f557..41573303 100644
--- a/include/commodity.h
+++ b/include/commodity.h
@@ -41,9 +41,11 @@
 #include "item.h"
 
 struct comstr {
+    /* initial part must match struct empobj */
     short ef_type;
     natid com_owner;
     short com_uid;
+    /* end of part matching struct empobj */
     i_type com_type;
     int com_amount;
     float com_price;
diff --git a/include/trade.h b/include/trade.h
index da1b5a8e..45b4dfe0 100644
--- a/include/trade.h
+++ b/include/trade.h
@@ -41,9 +41,11 @@
 #include "types.h"
 
 struct trdstr {
+    /* initial part must match struct empobj */
     short ef_type;
     natid trd_owner;
     short trd_uid;
+    /* end of part matching struct empobj */
     short trd_type;
     short trd_unitid;
     long trd_price;
diff --git a/src/lib/global/file.c b/src/lib/global/file.c
index 9db598fc..0a0031a6 100644
--- a/src/lib/global/file.c
+++ b/src/lib/global/file.c
@@ -131,7 +131,7 @@ struct empfile empfile[] = {
     {EF_TREATY, "treaty", "treaty", treaty_ca,
      UNMAPPED_CACHE(struct trtstr, 0)},
     {EF_TRADE, "trade", "trade", trade_ca,
-     UNMAPPED_CACHE(struct trdstr, 0)},
+     UNMAPPED_CACHE(struct trdstr, EFF_OWNER)},
     {EF_POWER, "pow", "power", NULL,
      UNMAPPED_CACHE(struct powstr, 0)},
     {EF_NATION, "nat", "nation", nat_ca,
@@ -143,7 +143,7 @@ struct empfile empfile[] = {
     {EF_BMAP, "bmap", "bmap", NULL,
      0, 0, NULL, 0, 0, 0, 0, -1, NULL, NULL, NULL},
     {EF_COMM, "commodity", "commodity", commodity_ca,
-     UNMAPPED_CACHE(struct comstr, 0)},
+     UNMAPPED_CACHE(struct comstr, EFF_OWNER)},
     {EF_LOST, "lost", "lostitems", lost_ca,
      UNMAPPED_CACHE(struct loststr, EFF_OWNER)},
     {EF_REALM, "realm", "realms", realm_ca,
@@ -214,7 +214,8 @@ struct empfile empfile[] = {
     SYMTAB(EF_TREATY_FLAGS, "treaty-flags", treaty_flags),
 
     /* Views */
-    {EF_COUNTRY, "country", NULL, cou_ca, UNMAPPED_CACHE(struct natstr, 0)},
+    {EF_COUNTRY, "country", NULL, cou_ca,
+     UNMAPPED_CACHE(struct natstr, EFF_OWNER)},
 
     /* Sentinel */
     {EF_BAD, NULL, NULL, NULL, 0, 0, NULL, 0, 0, 0, 0, -1, NULL, NULL, NULL},