diff --git a/rustfs/src/storage/ecfs.rs b/rustfs/src/storage/ecfs.rs
index 9f61045fe..1e7b9f7a6 100644
--- a/rustfs/src/storage/ecfs.rs
+++ b/rustfs/src/storage/ecfs.rs
@@ -23,6 +23,7 @@ use crate::storage::head_prefix::{head_prefix_not_found_message, probe_prefix_ha
 use crate::storage::helper::OperationHelper;
 use crate::storage::options::{filter_object_metadata, get_content_sha256};
 use crate::storage::readers::InMemoryAsyncReader;
+use crate::storage::s3_api::bucket::build_list_objects_output;
 use crate::storage::sse::{
     DecryptionRequest, EncryptionRequest, PrepareEncryptionRequest, check_encryption_metadata, sse_decryption, sse_encryption,
     sse_prepare_encryption, strip_managed_encryption_metadata,
@@ -3724,58 +3725,7 @@ impl S3 for FS {
             }))
             .await?;
 
-        Ok(v2_resp.map_output(|v2| {
-            // For ListObjects (v1) API, NextMarker should be the last item returned when truncated
-            // When both Contents and CommonPrefixes are present, NextMarker should be the
-            // lexicographically last item (either last key or last prefix)
-            let next_marker = if v2.is_truncated.unwrap_or(false) {
-                let last_key = v2
-                    .contents
-                    .as_ref()
-                    .and_then(|contents| contents.last())
-                    .and_then(|obj| obj.key.as_ref())
-                    .cloned();
-
-                let last_prefix = v2
-                    .common_prefixes
-                    .as_ref()
-                    .and_then(|prefixes| prefixes.last())
-                    .and_then(|prefix| prefix.prefix.as_ref())
-                    .cloned();
-
-                // NextMarker should be the lexicographically last item
-                // This matches S3 standard behavior
-                match (last_key, last_prefix) {
-                    (Some(k), Some(p)) => {
-                        // Return the lexicographically greater one
-                        if k > p { Some(k) } else { Some(p) }
-                    }
-                    (Some(k), None) => Some(k),
-                    (None, Some(p)) => Some(p),
-                    (None, None) => None,
-                }
-            } else {
-                None
-            };
-
-            // S3 API requires marker field in response, echoing back the request marker
-            // If no marker was provided in request, return empty string per S3 standard
-            let marker = Some(request_marker.unwrap_or_default());
-
-            ListObjectsOutput {
-                contents: v2.contents,
-                delimiter: v2.delimiter,
-                encoding_type: v2.encoding_type,
-                name: v2.name,
-                prefix: v2.prefix,
-                max_keys: v2.max_keys,
-                common_prefixes: v2.common_prefixes,
-                is_truncated: v2.is_truncated,
-                marker,
-                next_marker,
-                ..Default::default()
-            }
-        }))
+        Ok(v2_resp.map_output(move |v2| build_list_objects_output(v2, request_marker.clone())))
     }
 
     #[instrument(level = "debug", skip(self, req))]
diff --git a/rustfs/src/storage/s3_api/bucket.rs b/rustfs/src/storage/s3_api/bucket.rs
new file mode 100644
index 000000000..19fa3b1b9
--- /dev/null
+++ b/rustfs/src/storage/s3_api/bucket.rs
@@ -0,0 +1,126 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use s3s::dto::{ListObjectsOutput, ListObjectsV2Output};
+
+pub(crate) fn build_list_objects_output(v2: ListObjectsV2Output, request_marker: Option<String>) -> ListObjectsOutput {
+    let next_marker = calculate_next_marker(&v2);
+
+    // S3 API requires marker field in response, echoing back the request marker.
+    // If no marker was provided in request, return empty string per S3 standard.
+    let marker = Some(request_marker.unwrap_or_default());
+
+    ListObjectsOutput {
+        contents: v2.contents,
+        delimiter: v2.delimiter,
+        encoding_type: v2.encoding_type,
+        name: v2.name,
+        prefix: v2.prefix,
+        max_keys: v2.max_keys,
+        common_prefixes: v2.common_prefixes,
+        is_truncated: v2.is_truncated,
+        marker,
+        next_marker,
+        ..Default::default()
+    }
+}
+
+fn calculate_next_marker(v2: &ListObjectsV2Output) -> Option<String> {
+    // For ListObjects (v1) API, NextMarker should be the last item returned when truncated.
+    // When both Contents and CommonPrefixes are present, NextMarker should be the
+    // lexicographically last item (either last key or last prefix).
+    if !v2.is_truncated.unwrap_or(false) {
+        return None;
+    }
+
+    let last_key = v2
+        .contents
+        .as_ref()
+        .and_then(|contents| contents.last())
+        .and_then(|obj| obj.key.as_ref())
+        .cloned();
+
+    let last_prefix = v2
+        .common_prefixes
+        .as_ref()
+        .and_then(|prefixes| prefixes.last())
+        .and_then(|prefix| prefix.prefix.as_ref())
+        .cloned();
+
+    // NextMarker should be the lexicographically last item.
+    // This matches S3 standard behavior.
+    match (last_key, last_prefix) {
+        (Some(k), Some(p)) => {
+            if k > p {
+                Some(k)
+            } else {
+                Some(p)
+            }
+        }
+        (Some(k), None) => Some(k),
+        (None, Some(p)) => Some(p),
+        (None, None) => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::build_list_objects_output;
+    use s3s::dto::{CommonPrefix, ListObjectsV2Output, Object};
+
+    #[test]
+    fn test_list_objects_marker_echoes_request_value() {
+        let output = build_list_objects_output(ListObjectsV2Output::default(), Some("m-1".to_string()));
+        assert_eq!(output.marker, Some("m-1".to_string()));
+    }
+
+    #[test]
+    fn test_list_objects_marker_defaults_to_empty_string() {
+        let output = build_list_objects_output(ListObjectsV2Output::default(), None);
+        assert_eq!(output.marker, Some(String::new()));
+    }
+
+    #[test]
+    fn test_list_objects_next_marker_uses_lexicographically_last_item() {
+        let v2 = ListObjectsV2Output {
+            is_truncated: Some(true),
+            contents: Some(vec![Object {
+                key: Some("apple".to_string()),
+                ..Default::default()
+            }]),
+            common_prefixes: Some(vec![CommonPrefix {
+                prefix: Some("zebra/".to_string()),
+            }]),
+            ..Default::default()
+        };
+
+        let output = build_list_objects_output(v2, None);
+        assert_eq!(output.next_marker, Some("zebra/".to_string()));
+    }
+
+    #[test]
+    fn test_list_objects_next_marker_is_none_when_not_truncated() {
+        let v2 = ListObjectsV2Output {
+            is_truncated: Some(false),
+            contents: Some(vec![Object {
+                key: Some("only-item".to_string()),
+                ..Default::default()
+            }]),
+            ..Default::default()
+        };
+
+        let output = build_list_objects_output(v2, None);
+        assert_eq!(output.next_marker, None);
+    }
+}
diff --git a/rustfs/src/storage/s3_api/mod.rs b/rustfs/src/storage/s3_api/mod.rs
index 35921e90c..5fac73943 100644
--- a/rustfs/src/storage/s3_api/mod.rs
+++ b/rustfs/src/storage/s3_api/mod.rs
@@ -18,7 +18,7 @@
 //! until each helper is moved with dedicated small refactor steps.
 
 pub(crate) mod acl {}
-pub(crate) mod bucket {}
+pub(crate) mod bucket;
 pub(crate) mod encryption {}
 pub(crate) mod multipart {}
 /// Object helper facade placeholder.