 Since the 2010s, sources under government control tend to give him more distinguished titles like "Grand Ayatollah" and "Imam".Certain clerics have been downgraded by not being addressed as an Ayatollah, such as Mohammad Kazem Shariatmadari and Hussein-Ali Montazeri.Though no formal hierarchical structure exists among Shia clerics, a "hierarchy of difference" can be elaborated to describe the situation.