diff --git a/programs/mango-v4/src/instructions/perp_consume_events.rs b/programs/mango-v4/src/instructions/perp_consume_events.rs
index bbc2e7ef1..b45ad8043 100644
--- a/programs/mango-v4/src/instructions/perp_consume_events.rs
+++ b/programs/mango-v4/src/instructions/perp_consume_events.rs
@@ -130,7 +130,6 @@ pub fn perp_consume_events(ctx: Context<PerpConsumeEvents>, limit: usize) -> Res
                     seq_num: fill.seq_num,
                     maker: fill.maker,
                     maker_order_id: fill.maker_order_id,
-                    maker_client_order_id: fill.maker_client_order_id,
                     maker_fee: fill.maker_fee.to_bits(),
                     maker_timestamp: fill.maker_timestamp,
                     taker: fill.taker,
diff --git a/programs/mango-v4/src/logs.rs b/programs/mango-v4/src/logs.rs
index dff3ae48d..56183a948 100644
--- a/programs/mango-v4/src/logs.rs
+++ b/programs/mango-v4/src/logs.rs
@@ -100,7 +100,6 @@ pub struct FillLog {
 
     pub maker: Pubkey,
     pub maker_order_id: u128,
-    pub maker_client_order_id: u64,
     pub maker_fee: i128,
 
     // Timestamp of when the maker order was placed; copied over from the LeafNode
diff --git a/programs/mango-v4/src/state/mango_account.rs b/programs/mango-v4/src/state/mango_account.rs
index 04472dd4f..2a19e2c72 100644
--- a/programs/mango-v4/src/state/mango_account.rs
+++ b/programs/mango-v4/src/state/mango_account.rs
@@ -811,6 +811,7 @@ impl<
         side: Side,
         order_tree: BookSideOrderTree,
         order: &LeafNode,
+        client_order_id: u64,
     ) -> Result<()> {
         let mut perp_account = self.perp_position_mut(perp_market_index)?;
         match side {
@@ -827,7 +828,7 @@ impl<
         oo.market = perp_market_index;
         oo.side_and_tree = SideAndOrderTree::new(side, order_tree).into();
         oo.id = order.key;
-        oo.client_id = order.client_order_id;
+        oo.client_id = client_order_id;
         Ok(())
     }
 
diff --git a/programs/mango-v4/src/state/orderbook/book.rs b/programs/mango-v4/src/state/orderbook/book.rs
index 723d6dd49..168a6d4dd 100644
--- a/programs/mango-v4/src/state/orderbook/book.rs
+++ b/programs/mango-v4/src/state/orderbook/book.rs
@@ -180,7 +180,6 @@ impl<'a> Orderbook<'a> {
                 event_queue.header.seq_num,
                 best_opposing.node.owner,
                 best_opposing.node.key,
-                best_opposing.node.client_order_id,
                 market.maker_fee,
                 best_opposing.node.timestamp,
                 *mango_account_pk,
@@ -259,7 +258,6 @@ impl<'a> Orderbook<'a> {
                 order_id,
                 *mango_account_pk,
                 book_base_quantity,
-                order.client_order_id,
                 now_ts,
                 PostOrderType::Limit, // TODO: Support order types? needed?
                 order.time_in_force,
@@ -284,6 +282,7 @@ impl<'a> Orderbook<'a> {
                 side,
                 order_tree_target,
                 &new_order,
+                order.client_order_id,
             )?;
         }
 
diff --git a/programs/mango-v4/src/state/orderbook/bookside.rs b/programs/mango-v4/src/state/orderbook/bookside.rs
index f5af2bc82..ac050f7ec 100644
--- a/programs/mango-v4/src/state/orderbook/bookside.rs
+++ b/programs/mango-v4/src/state/orderbook/bookside.rs
@@ -164,19 +164,8 @@ mod tests {
         let mut order_tree = new_order_tree(order_tree_type);
         let mut root_fixed = OrderTreeRoot::zeroed();
         let mut root_pegged = OrderTreeRoot::zeroed();
-        let new_leaf = |key: u128| {
-            LeafNode::new(
-                0,
-                key,
-                Pubkey::default(),
-                0,
-                0,
-                1,
-                PostOrderType::Limit,
-                0,
-                -1,
-            )
-        };
+        let new_leaf =
+            |key: u128| LeafNode::new(0, key, Pubkey::default(), 0, 1, PostOrderType::Limit, 0, -1);
 
         // add 100 leaves to each BookSide, mostly random
         let mut keys = vec![];
@@ -266,7 +255,6 @@ mod tests {
                 key,
                 Pubkey::default(),
                 0,
-                0,
                 1000,
                 PostOrderType::Limit,
                 tif,
diff --git a/programs/mango-v4/src/state/orderbook/mod.rs b/programs/mango-v4/src/state/orderbook/mod.rs
index 15db0b69e..b100075dd 100644
--- a/programs/mango-v4/src/state/orderbook/mod.rs
+++ b/programs/mango-v4/src/state/orderbook/mod.rs
@@ -383,7 +383,6 @@ mod tests {
         assert_eq!(fill.quantity, match_quantity);
         assert_eq!(fill.price, price_lots);
         assert_eq!(fill.taker_client_order_id, 43);
-        assert_eq!(fill.maker_client_order_id, 42);
         assert_eq!(fill.maker, maker_pk);
         assert_eq!(fill.taker, taker_pk);
         assert_eq!(fill.maker_fee, market.maker_fee);
diff --git a/programs/mango-v4/src/state/orderbook/nodes.rs b/programs/mango-v4/src/state/orderbook/nodes.rs
index bb3839744..7dffb2c5a 100644
--- a/programs/mango-v4/src/state/orderbook/nodes.rs
+++ b/programs/mango-v4/src/state/orderbook/nodes.rs
@@ -140,7 +140,6 @@ pub struct LeafNode {
 
     pub owner: Pubkey,
     pub quantity: i64,
-    pub client_order_id: u64,
 
     // The time the order was placed
     pub timestamp: u64,
@@ -148,11 +147,11 @@ pub struct LeafNode {
     // Only applicable in the oracle_pegged OrderTree
     pub peg_limit: i64,
 
-    pub reserved: [u8; 32],
+    pub reserved: [u8; 40],
 }
 const_assert_eq!(
     size_of::<LeafNode>(),
-    4 + 1 + 1 + 1 + 1 + 16 + 32 + 8 + 8 + 8 + 8 + 32
+    4 + 1 + 1 + 1 + 1 + 16 + 32 + 8 + 8 + 8 + 40
 );
 const_assert_eq!(size_of::<LeafNode>(), NODE_SIZE);
 const_assert_eq!(size_of::<LeafNode>() % 8, 0);
@@ -164,7 +163,6 @@ impl LeafNode {
         key: u128,
         owner: Pubkey,
         quantity: i64,
-        client_order_id: u64,
         timestamp: u64,
         order_type: PostOrderType,
         time_in_force: u16,
@@ -180,10 +178,9 @@ impl LeafNode {
             key,
             owner,
             quantity,
-            client_order_id,
             timestamp,
             peg_limit,
-            reserved: [0; 32],
+            reserved: [0; 40],
         }
     }
 
diff --git a/programs/mango-v4/src/state/orderbook/ordertree.rs b/programs/mango-v4/src/state/orderbook/ordertree.rs
index 343ae3491..edd8bc1c8 100644
--- a/programs/mango-v4/src/state/orderbook/ordertree.rs
+++ b/programs/mango-v4/src/state/orderbook/ordertree.rs
@@ -544,7 +544,6 @@ mod tests {
                 key,
                 Pubkey::default(),
                 0,
-                0,
                 expiry - 1,
                 PostOrderType::Limit,
                 1,
@@ -637,7 +636,6 @@ mod tests {
                 key,
                 Pubkey::default(),
                 0,
-                0,
                 expiry - 1,
                 PostOrderType::Limit,
                 1,
diff --git a/programs/mango-v4/src/state/orderbook/queue.rs b/programs/mango-v4/src/state/orderbook/queue.rs
index c8d10f921..63cc77750 100644
--- a/programs/mango-v4/src/state/orderbook/queue.rs
+++ b/programs/mango-v4/src/state/orderbook/queue.rs
@@ -191,7 +191,6 @@ pub struct FillEvent {
 
     pub maker: Pubkey,
     pub maker_order_id: u128,
-    pub maker_client_order_id: u64,
     pub maker_fee: I80F48,
 
     // Timestamp of when the maker order was placed; copied over from the LeafNode
@@ -204,7 +203,7 @@ pub struct FillEvent {
 
     pub price: i64,
     pub quantity: i64, // number of quote lots
-    pub reserved: [u8; 16],
+    pub reserved: [u8; 24],
 }
 const_assert_eq!(size_of::<FillEvent>() % 8, 0);
 const_assert_eq!(size_of::<FillEvent>(), EVENT_SIZE);
@@ -219,7 +218,6 @@ impl FillEvent {
         seq_num: u64,
         maker: Pubkey,
         maker_order_id: u128,
-        maker_client_order_id: u64,
         maker_fee: I80F48,
         maker_timestamp: u64,
 
@@ -241,7 +239,6 @@ impl FillEvent {
             seq_num,
             maker,
             maker_order_id,
-            maker_client_order_id,
             maker_fee,
             maker_timestamp,
             taker,
@@ -250,7 +247,7 @@ impl FillEvent {
             taker_fee,
             price,
             quantity,
-            reserved: [0; 16],
+            reserved: [0; 24],
         }
     }
 
diff --git a/ts/client/src/accounts/perp.ts b/ts/client/src/accounts/perp.ts
index 6c5730c1b..a2ee9f5e2 100644
--- a/ts/client/src/accounts/perp.ts
+++ b/ts/client/src/accounts/perp.ts
@@ -960,7 +960,6 @@ export interface FillEvent extends Event {
   seqNum: BN;
   maker: PublicKey;
   makerOrderId: BN;
-  makerClientOrderId: BN;
   makerFee: I80F48;
   makerTimestamp: BN;
   taker: PublicKey;
diff --git a/ts/client/src/mango_v4.ts b/ts/client/src/mango_v4.ts
index 82f820faa..35026663c 100644
--- a/ts/client/src/mango_v4.ts
+++ b/ts/client/src/mango_v4.ts
@@ -5442,10 +5442,6 @@ export type MangoV4 = {
             "name": "quantity",
             "type": "i64"
           },
-          {
-            "name": "clientOrderId",
-            "type": "u64"
-          },
           {
             "name": "timestamp",
             "type": "u64"
@@ -5459,7 +5455,7 @@ export type MangoV4 = {
             "type": {
               "array": [
                 "u8",
-                32
+                40
               ]
             }
           }
@@ -5654,10 +5650,6 @@ export type MangoV4 = {
             "name": "makerOrderId",
             "type": "u128"
           },
-          {
-            "name": "makerClientOrderId",
-            "type": "u64"
-          },
           {
             "name": "makerFee",
             "type": {
@@ -5699,7 +5691,7 @@ export type MangoV4 = {
             "type": {
               "array": [
                 "u8",
-                16
+                24
               ]
             }
           }
@@ -6506,11 +6498,6 @@ export type MangoV4 = {
           "type": "u128",
           "index": false
         },
-        {
-          "name": "makerClientOrderId",
-          "type": "u64",
-          "index": false
-        },
         {
           "name": "makerFee",
           "type": "i128",
@@ -12799,10 +12786,6 @@ export const IDL: MangoV4 = {
             "name": "quantity",
             "type": "i64"
           },
-          {
-            "name": "clientOrderId",
-            "type": "u64"
-          },
           {
             "name": "timestamp",
             "type": "u64"
@@ -12816,7 +12799,7 @@ export const IDL: MangoV4 = {
             "type": {
               "array": [
                 "u8",
-                32
+                40
               ]
             }
           }
@@ -13011,10 +12994,6 @@ export const IDL: MangoV4 = {
             "name": "makerOrderId",
             "type": "u128"
           },
-          {
-            "name": "makerClientOrderId",
-            "type": "u64"
-          },
           {
             "name": "makerFee",
             "type": {
@@ -13056,7 +13035,7 @@ export const IDL: MangoV4 = {
             "type": {
               "array": [
                 "u8",
-                16
+                24
               ]
             }
           }
@@ -13863,11 +13842,6 @@ export const IDL: MangoV4 = {
           "type": "u128",
           "index": false
         },
-        {
-          "name": "makerClientOrderId",
-          "type": "u64",
-          "index": false
-        },
         {
           "name": "makerFee",
           "type": "i128",