diff --git a/src/search.cpp b/src/search.cpp
index 06c6e198..2b95043f 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1053,11 +1053,9 @@ moves_loop:  // When in check, search starts here
                     int doubleMargin = 285 * PvNode - 228 * !ttCapture;
                     int tripleMargin =
                       121 + 238 * PvNode - 259 * !ttCapture + 117 * (ss->ttPv || !ttCapture);
-                    int quadMargin = 471 + 343 * PvNode - 281 * !ttCapture + 217 * ss->ttPv;
 
                     extension = 1 + (value < singularBeta - doubleMargin)
-                              + (value < singularBeta - tripleMargin)
-                              + (value < singularBeta - quadMargin);
+                              + (value < singularBeta - tripleMargin);
 
                     depth += ((!PvNode) && (depth < 14));
                 }