diff --git a/DuckDuckGo/Bookmarks/Model/BookmarkList.swift b/DuckDuckGo/Bookmarks/Model/BookmarkList.swift
index de5473a1c8..b7c9c6a64c 100644
--- a/DuckDuckGo/Bookmarks/Model/BookmarkList.swift
+++ b/DuckDuckGo/Bookmarks/Model/BookmarkList.swift
@@ -160,7 +160,9 @@ struct BookmarkList {
     private mutating func updateLowercasedItemsDict() {
         lowercasedItemsDict = itemsDict.reduce(into: [:]) { result, entry in
             let lowercasedKey = entry.key.lowercased()
-            result[lowercasedKey] = entry.value
+            if result[lowercasedKey] == nil {
+                result[lowercasedKey] = entry.value
+            }
         }
     }
 
diff --git a/UnitTests/Bookmarks/Model/BookmarkListTests.swift b/UnitTests/Bookmarks/Model/BookmarkListTests.swift
index f0f8cda903..688a6da30a 100644
--- a/UnitTests/Bookmarks/Model/BookmarkListTests.swift
+++ b/UnitTests/Bookmarks/Model/BookmarkListTests.swift
@@ -180,6 +180,92 @@ final class BookmarkListTests: XCTestCase {
         XCTAssertEqual(result.isFavorite, false)
     }
 
+    func testWhenBookmarkIsInserted_ThenLowercasedItemsDictContainsLowercasedKey() {
+        var bookmarkList = BookmarkList()
+
+        let bookmark = Bookmark.aCaseSensitiveBookmark
+        bookmarkList.insert(bookmark)
+
+        let lowercasedKey = bookmark.url.lowercased()
+        let items = bookmarkList.lowercasedItemsDict[lowercasedKey]
+
+        XCTAssertNotNil(items)
+        XCTAssertEqual(items?.count, 1)
+        XCTAssertEqual(items?.first?.id, bookmark.id)
+    }
+
+    func testWhenBookmarkIsRemoved_ThenLowercasedItemsDictDoesNotContainBookmark() {
+        var bookmarkList = BookmarkList()
+
+        let bookmark = Bookmark.aCaseSensitiveBookmark
+        bookmarkList.insert(bookmark)
+
+        bookmarkList.remove(bookmark)
+
+        let lowercasedKey = bookmark.url.lowercased()
+        let items = bookmarkList.lowercasedItemsDict[lowercasedKey]
+
+        XCTAssertNil(items)
+    }
+
+    func testWhenBookmarkUrlIsUpdated_ThenLowercasedItemsDictReflectsUpdatedUrl() throws {
+        var bookmarkList = BookmarkList()
+
+        let bookmark = Bookmark.aCaseSensitiveBookmark
+        bookmarkList.insert(bookmark)
+
+        let newURL = "www.example.com"
+        let updatedBookmark = try XCTUnwrap(bookmarkList.updateUrl(of: bookmark, to: newURL))
+
+        let originalKey = bookmark.url.lowercased()
+        let newKey = newURL.lowercased()
+
+        XCTAssertEqual(bookmarkList.lowercasedItemsDict[originalKey], [])
+        XCTAssertNotNil(bookmarkList.lowercasedItemsDict[newKey])
+
+        let items = bookmarkList.lowercasedItemsDict[newKey]
+        XCTAssertEqual(items?.count, 1)
+        XCTAssertEqual(items?.first?.id, updatedBookmark.id)
+        XCTAssertEqual(items?.first?.url, updatedBookmark.url)
+    }
+
+    func testWhenBookmarkIsUpdatedWithNewTitleAndFavoriteStatus_ThenLowercasedItemsDictPreservesKey() {
+        var bookmarkList = BookmarkList()
+
+        let bookmark = Bookmark.aCaseSensitiveBookmark
+        bookmarkList.insert(bookmark)
+
+        let newTitle = "Updated Title"
+        let newIsFavorite = !bookmark.isFavorite
+        let updatedBookmark = bookmarkList.update(bookmark: bookmark, newURL: bookmark.url, newTitle: newTitle, newIsFavorite: newIsFavorite)
+
+        let lowercasedKey = bookmark.url.lowercased()
+        let items = bookmarkList.lowercasedItemsDict[lowercasedKey]
+
+        XCTAssertNotNil(items)
+        XCTAssertEqual(items?.count, 1)
+        XCTAssertEqual(items?.first?.id, updatedBookmark?.id)
+        XCTAssertEqual(items?.first?.title, newTitle)
+        XCTAssertEqual(items?.first?.isFavorite, newIsFavorite)
+    }
+
+    func testWhenMultipleBookmarksWithSameURLDifferentCasesAreInserted_ThenLowercasedItemsDictContainsFirstOne() {
+        var bookmarkList = BookmarkList()
+
+        let bookmark1 = Bookmark(id: UUID().uuidString, url: "www.Example.com", title: "Example 1", isFavorite: true)
+        let bookmark2 = Bookmark(id: UUID().uuidString, url: "www.example.COM", title: "Example 2", isFavorite: false)
+
+        bookmarkList.insert(bookmark1)
+        bookmarkList.insert(bookmark2)
+
+        let lowercasedKey = "www.example.com"
+        let items = bookmarkList.lowercasedItemsDict[lowercasedKey]
+
+        XCTAssertNotNil(items)
+        XCTAssertTrue(items?.contains(where: { $0.id == bookmark1.id }) ?? false)
+        XCTAssertFalse(items?.contains(where: { $0.id == bookmark2.id }) ?? false)
+    }
+
 }
 
 fileprivate extension Bookmark {
@@ -191,6 +277,13 @@ fileprivate extension Bookmark {
                                               isFavorite: false,
                                               faviconManagement: FaviconManagerMock())
 
+    @MainActor(unsafe)
+    static var aCaseSensitiveBookmark: Bookmark = Bookmark(id: UUID().uuidString,
+                                              url: "www.DuckDuckGo.com",
+                                              title: "Title",
+                                              isFavorite: false,
+                                              faviconManagement: FaviconManagerMock())
+
     var identifiableBookmark: BookmarkList.IdentifiableBookmark {
         return BookmarkList.IdentifiableBookmark(from: self)
     }