diff --git a/MailCore/Models/Thread.swift b/MailCore/Models/Thread.swift
index f05c69875..df6436081 100644
--- a/MailCore/Models/Thread.swift
+++ b/MailCore/Models/Thread.swift
@@ -42,7 +42,7 @@ public class Thread: Object, Decodable, Identifiable {
     @Persisted public var cc: List<Recipient>
     @Persisted public var bcc: List<Recipient>
     @Persisted public var subject: String?
-    @Persisted public var date: Date
+    @Persisted(indexed: true) public var date: Date
     @Persisted public var hasAttachments: Bool
     @Persisted public var hasSwissTransferAttachments: Bool
     @Persisted public var hasDrafts: Bool