diff --git a/src/arx.jl b/src/arx.jl
index bb6dc0eca7418666104d669345bb96be3978b2f4..13017c2c2318e7282da617dd0cee807998f64af6 100644
--- a/src/arx.jl
+++ b/src/arx.jl
@@ -131,7 +131,7 @@ bodeconfidence
     arxtfm = p.args[1]
     Σ      = p.args[2]
     L      = chol(Hermitian(Σ))
-    am, bm = -denpoly(arxtfm)[1].a[2:end], arxtfm.matrix[1].num.a
+    am, bm = -reverse(denpoly(arxtfm)[1].a[1:end-1]), reverse(arxtfm.matrix[1].num.a)
     wm     = [am; bm]
     na,nb  = length(am), length(bm)
     mc     = 100