diff --git a/src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionServiceImpl.tjava b/src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionServiceImpl.tjava
index 71da1a4..259d9e7 100644
--- a/src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionServiceImpl.tjava
+++ b/src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionServiceImpl.tjava
@@ -41,26 +41,36 @@ public class AnchorIdlJupiterPerpsPositionServiceImpl implements JupiterPerpsPos
     @Override
     public Set<JupiterPerpsPosition> getOpenPositions(ΩSolanaWalletIdΩ owner)
             throws IOException, InterruptedException {
-    Set<SolanaAccountInfo> accountInfos = solanaBlockChain.getProgramAccounts(
-            JUPITER_PERPS_PROGRAM_ID,
-            Set.of(new SolanaProgramAccountMemcmpFilter(
-                    POSITION_OWNER_OFFSET,
-                    owner
-            ))
+        Set<SolanaAccountInfo> accountInfos = solanaBlockChain.getProgramAccounts(
+                JUPITER_PERPS_PROGRAM_ID,
+                Set.of(new SolanaProgramAccountMemcmpFilter(
+                        POSITION_OWNER_OFFSET,
+                        owner
+                ))
         );
 
-    Set<JupiterPerpsPosition> positions = new HashSet<>();
+        Set<JupiterPerpsPosition> positions = new HashSet<>();
 
-    for (SolanaAccountInfo accountInfo : accountInfos) {
-        JupiterPerpsPosition position = positionDecoder.decode(
-                accountInfo.address(),
-                accountInfo
-        );
-        positions.add(position);
+        for (SolanaAccountInfo accountInfo : accountInfos) {
+            ΩSolanaAddressΩ address = accountInfo.address();
+            ΩSolanaProgramIdΩ programId = accountInfo.owner();
+
+            if (!JUPITER_PERPS_PROGRAM_ID.equals(programId)) {
+                String errorMsg = "Account '" + address + "' is not owned by Jupiter Perps program '" +
+                        programId + "'";
+                throw new IllegalArgumentException(errorMsg);
+            }
+
+            JupiterPerpsPosition position = positionDecoder.decode(
+                    address,
+                    accountInfo
+            );
+            positions.add(position);
+        }
+
+        return Set.copyOf(positions);
     }
 
-    return Set.copyOf(positions);
-}
     private static final ΩJupiterPerpsProgramIdΩ JUPITER_PERPS_PROGRAM_ID =
             "PERPHjGBqRHArX4DySjwM6UJHiR3sWAatqfdBS2qQJu";
     private static final int POSITION_OWNER_OFFSET = 8;