diff --git a/programs/mango-v4/src/error.rs b/programs/mango-v4/src/error.rs
index 5f1cc9429..c8ebeaf6b 100644
--- a/programs/mango-v4/src/error.rs
+++ b/programs/mango-v4/src/error.rs
@@ -12,4 +12,6 @@ pub enum MangoError {
     UnknownOracleType,
     #[msg("")]
     InvalidMarginTradeTargetCpiProgram,
+    #[msg("")]
+    HealthMustBePositive,
 }
diff --git a/programs/mango-v4/src/instructions/margin_trade.rs b/programs/mango-v4/src/instructions/margin_trade.rs
index 5b20ad61f..06eef9591 100644
--- a/programs/mango-v4/src/instructions/margin_trade.rs
+++ b/programs/mango-v4/src/instructions/margin_trade.rs
@@ -33,7 +33,7 @@ pub fn margin_trade(ctx: Context<MarginTrade>, cpi_data: Vec<u8>) -> Result<()>
     // abuse this ix to do unwanted changes
     for cpi_ai in cpi_ais {
         require!(
-            *ctx.remaining_accounts[active_len].key != Mango::id(),
+            cpi_ai.key() != Mango::id(),
             MangoError::InvalidMarginTradeTargetCpiProgram
         );
     }