diff --git a/doc/wildcards.rst b/doc/wildcards.rst
index 19b7074e..8a177613 100644
--- a/doc/wildcards.rst
+++ b/doc/wildcards.rst
@@ -73,7 +73,7 @@ The wildcard, in general, consists of two parts:
        
        (a) If ``opt`` is chosen line expansion is optimised
            according to its capital cost
-           (where the choice ``v`` only considers overhead costs and
+           (where the choice ``v`` only considers overhead costs for HVDC transmission lines, while
            ``c`` uses more accurate costs distinguishing between
            overhead and underwater sections and including inverter pairs).
 
@@ -188,4 +188,4 @@ formats depends on the used backend. To query the supported file types on your s
     plt.gcf().canvas.get_supported_filetypes()
 
 .. seealso::
-    :mod:`plot_network`, :mod:`plot_summary`, :mod:`plot_p_nom_max`
\ No newline at end of file
+    :mod:`plot_network`, :mod:`plot_summary`, :mod:`plot_p_nom_max`