diff --git a/include/boost/math/tools/polynomial.hpp b/include/boost/math/tools/polynomial.hpp
index 73980d6aa..c69a1ea53 100644
--- a/include/boost/math/tools/polynomial.hpp
+++ b/include/boost/math/tools/polynomial.hpp
@@ -408,7 +408,7 @@ public:
        return *this;
    }
    template <class U>
-   polynomial& operator *=(const polynomial<U>& value)
+   polynomial& operator *=(const polynomial<U> value)
    {
       // TODO: FIXME: use O(N log(N)) algorithm!!!
       polynomial const zero = zero_element(std::multiplies<polynomial>());