a security element for application or embedding in objects , in particular for documents of value such as bank notes , credit cards and the like , is structured in a multi - layer fashion and has an interference element i , which produces a color shift effect , a layer m with magnetic properties and a reflection layer r , which is located between interference element i and magnetic layer m . designs of the invention pro - vide a negative writing 20 and / or coding 11 in reflection layer r and magnetic layer m . according to a further design diffraction structures 2 are integrated in the security element 1 . such a security element in particular is suitable as window security thread 200 in bank notes .