diff --git a/crates/rbuilder-primitives/src/lib.rs b/crates/rbuilder-primitives/src/lib.rs
index fb753b207..49848a74f 100644
--- a/crates/rbuilder-primitives/src/lib.rs
+++ b/crates/rbuilder-primitives/src/lib.rs
@@ -52,7 +52,7 @@ pub struct Metadata {
     /// Order refund identity.
     pub refund_identity: Option<Address>,
     /// `RawBundle` field, round-tripped through `Bundle`. Not consumed by rbuilder.
-    pub disable_cross_region_sharing: Option<bool>,
+    pub disable_cross_region_sharing: bool,
 }
 
 impl Default for Metadata {
@@ -73,7 +73,7 @@ impl Metadata {
             received_at_timestamp,
             is_system: false,
             refund_identity: None,
-            disable_cross_region_sharing: None,
+            disable_cross_region_sharing: false,
         }
     }
 
@@ -99,17 +99,10 @@ impl Metadata {
         self.refund_identity = refund_identity;
     }
 
-    pub fn with_disable_cross_region_sharing(
-        mut self,
-        disable_cross_region_sharing: Option<bool>,
-    ) -> Self {
+    pub fn with_disable_cross_region_sharing(mut self, disable_cross_region_sharing: bool) -> Self {
         self.disable_cross_region_sharing = disable_cross_region_sharing;
         self
     }
-
-    pub fn set_disable_cross_region_sharing(&mut self, disable_cross_region_sharing: Option<bool>) {
-        self.disable_cross_region_sharing = disable_cross_region_sharing;
-    }
 }
 
 impl InMemorySize for Metadata {
@@ -117,7 +110,7 @@ impl InMemorySize for Metadata {
         mem::size_of::<time::OffsetDateTime>() + // received_at_timestamp
             mem::size_of::<Option<Address>>() + // refund_identity
             mem::size_of::<bool>() + // is_system
-            mem::size_of::<Option<bool>>() // disable_cross_region_sharing
+            mem::size_of::<bool>() // disable_cross_region_sharing
     }
 }
 
diff --git a/crates/rbuilder-primitives/src/serialize.rs b/crates/rbuilder-primitives/src/serialize.rs
index c423aa9aa..d11436eb2 100644
--- a/crates/rbuilder-primitives/src/serialize.rs
+++ b/crates/rbuilder-primitives/src/serialize.rs
@@ -154,8 +154,12 @@ pub struct RawBundleMetadata {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub bundle_hash: Option<B256>,
     /// Disable multiplexing bundle to other region builders.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub disable_cross_region_sharing: Option<bool>,
+    #[serde(default, skip_serializing_if = "is_false")]
+    pub disable_cross_region_sharing: bool,
+}
+
+fn is_false(b: &bool) -> bool {
+    !*b
 }
 
 impl RawBundleMetadata {
@@ -234,7 +238,7 @@ impl RawBundleMetadata {
                         version,
                     ));
                 }
-                if self.disable_cross_region_sharing.is_some() {
+                if self.disable_cross_region_sharing {
                     return Err(RawBundleConvertError::FieldNotSupportedByVersion(
                         "disable_cross_region_sharing".to_owned(),
                         version,
diff --git a/crates/rbuilder/src/backtest/build_block/synthetic_orders.rs b/crates/rbuilder/src/backtest/build_block/synthetic_orders.rs
index 6c6af52cd..3f337eef7 100644
--- a/crates/rbuilder/src/backtest/build_block/synthetic_orders.rs
+++ b/crates/rbuilder/src/backtest/build_block/synthetic_orders.rs
@@ -98,7 +98,7 @@ impl<ConfigType: LiveBuilderConfig> SyntheticOrdersSource<ConfigType> {
                     received_at_timestamp: time::OffsetDateTime::from_unix_timestamp(0).unwrap(),
                     is_system: false,
                     refund_identity: None,
-                    disable_cross_region_sharing: None,
+                    disable_cross_region_sharing: false,
                 },
                 dropping_tx_hashes: Default::default(),
                 refund: None,
diff --git a/crates/rbuilder/src/backtest/store.rs b/crates/rbuilder/src/backtest/store.rs
index b5bef21b2..3311c239e 100644
--- a/crates/rbuilder/src/backtest/store.rs
+++ b/crates/rbuilder/src/backtest/store.rs
@@ -744,7 +744,7 @@ mod test {
                         refund_identity: None,
                         version: Some(RawBundle::encode_version(LAST_BUNDLE_VERSION)),
                         bundle_hash: None,
-                        disable_cross_region_sharing: None,
+                        disable_cross_region_sharing: false,
                     },
                 })),
             }