diff --git a/ql/instruments/overnightindexedswap.cpp b/ql/instruments/overnightindexedswap.cpp
index 949fe31846..b93a194669 100644
--- a/ql/instruments/overnightindexedswap.cpp
+++ b/ql/instruments/overnightindexedswap.cpp
@@ -54,7 +54,7 @@ namespace QuantLib {
 
     OvernightIndexedSwap::OvernightIndexedSwap(Type type,
                                                const std::vector<Real>& nominals,
-                                               Schedule schedule,
+                                               const Schedule& schedule,
                                                Rate fixedRate,
                                                DayCounter fixedDC,
                                                const ext::shared_ptr<OvernightIndex>& overnightIndex,
diff --git a/ql/instruments/overnightindexedswap.hpp b/ql/instruments/overnightindexedswap.hpp
index 89ce778f61..58b2775651 100644
--- a/ql/instruments/overnightindexedswap.hpp
+++ b/ql/instruments/overnightindexedswap.hpp
@@ -56,7 +56,7 @@ namespace QuantLib {
 
         OvernightIndexedSwap(Type type,
                              const std::vector<Real>& nominals,
-                             Schedule schedule,
+                             const Schedule& schedule,
                              Rate fixedRate,
                              DayCounter fixedDC,
                              const ext::shared_ptr<OvernightIndex>& overnightIndex,