X Limited was holding 100% of the equity share capital of Y Limited and Y Limited was treated as a subsidiary by X Limited. Now, Y Limited issues convertible preference shares to Z Limited. As per the issue document of convertible preference shares, Z Limited also gets the rights to participate in the relevant activities of Y Limited whereby Z Limited's consent is also necessary to pass any decision by the equity shareholder of Y Limited (i.e. X Limited). Determine how should X Limited account for its investment in Y Limited in its consolidated financial statements after the issue of convertible preference shares by Y Limited to Z Limited?