diff --git a/src/module.mk b/src/module.mk
index 496a46810..09373688f 100644
--- a/src/module.mk
+++ b/src/module.mk
@@ -17,6 +17,7 @@ LIBFLEXI_SRC := \
 		$(DIR)/gsl_utils.cpp \
 		$(DIR)/linalg.cpp \
 		$(DIR)/lowe.cpp \
+		$(DIR)/observables.cpp \
 		$(DIR)/sfermions.cpp \
 		$(DIR)/mssm_twoloophiggs.f \
 		$(DIR)/nmssm2loop.f \
@@ -75,6 +76,7 @@ LIBFLEXI_HDR := \
 		$(DIR)/nmssm_twoloophiggs.h \
 		$(DIR)/numerics.h \
 		$(DIR)/numerics2.hpp \
+		$(DIR)/observables.hpp \
 		$(DIR)/pmns.hpp \
 		$(DIR)/problems.hpp \
 		$(DIR)/pv.hpp \
diff --git a/src/observables.cpp b/src/observables.cpp
new file mode 100644
index 000000000..f5f0dff75
--- /dev/null
+++ b/src/observables.cpp
@@ -0,0 +1,33 @@
+// ====================================================================
+// This file is part of FlexibleSUSY.
+//
+// FlexibleSUSY is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published
+// by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// FlexibleSUSY is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with FlexibleSUSY.  If not, see
+// <http://www.gnu.org/licenses/>.
+// ====================================================================
+
+#include "observables.hpp"
+
+namespace flexiblesusy {
+
+Observables::Observables()
+   : amu(0.)
+{
+}
+
+void Observables::clear()
+{
+   amu = 0.;
+}
+
+} // namespace flexiblesusy
diff --git a/src/observables.hpp b/src/observables.hpp
new file mode 100644
index 000000000..13701539e
--- /dev/null
+++ b/src/observables.hpp
@@ -0,0 +1,38 @@
+// ====================================================================
+// This file is part of FlexibleSUSY.
+//
+// FlexibleSUSY is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published
+// by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// FlexibleSUSY is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with FlexibleSUSY.  If not, see
+// <http://www.gnu.org/licenses/>.
+// ====================================================================
+
+/**
+ * @file observables.hpp
+ * @brief contains class Observables
+ */
+
+#ifndef OBSERVABLES_H
+#define OBSERVABLES_H
+
+namespace flexiblesusy {
+
+struct Observables {
+   Observables();
+   void clear(); ///< sets all observables to zero
+
+   double amu;   ///< a_mu = (g-2)/2 of the muon
+};
+
+} // namespace flexiblesusy
+
+#endif