diff --git a/include/boost/serialization/factory.hpp b/include/boost/serialization/factory.hpp
index 8b092cba6..a73f8202a 100644
--- a/include/boost/serialization/factory.hpp
+++ b/include/boost/serialization/factory.hpp
@@ -21,6 +21,8 @@
 
 #include <boost/preprocessor/control/if.hpp>
 #include <boost/preprocessor/comparison/greater.hpp>
+#include <boost/preprocessor/facilities/empty.hpp>
+#include <boost/preprocessor/punctuation/comma.hpp>
 #include <boost/assert.hpp>
 
 namespace std{
@@ -59,15 +61,15 @@ namespace serialization {                                 \
         return new T(                                     \
             BOOST_PP_IF(BOOST_PP_GREATER(N, 0)            \
                 , a0, BOOST_PP_EMPTY())                   \
-            BOOST_PP_IF(BOOST_PP_GREATER(N, 1))           \
+            BOOST_PP_IF(BOOST_PP_GREATER(N, 1)            \
                 , BOOST_PP_COMMA, BOOST_PP_EMPTY)()       \
             BOOST_PP_IF(BOOST_PP_GREATER(N, 1)            \
                 , a1, BOOST_PP_EMPTY())                   \
-            BOOST_PP_IF(BOOST_PP_GREATER(N, 2))           \
+            BOOST_PP_IF(BOOST_PP_GREATER(N, 2)            \
                 , BOOST_PP_COMMA, BOOST_PP_EMPTY)()       \
             BOOST_PP_IF(BOOST_PP_GREATER(N, 2)            \
                 , a2, BOOST_PP_EMPTY())                   \
-            BOOST_PP_IF(BOOST_PP_GREATER(N, 3))           \
+            BOOST_PP_IF(BOOST_PP_GREATER(N, 3)            \
                 , BOOST_PP_COMMA, BOOST_PP_EMPTY)()       \
             BOOST_PP_IF(BOOST_PP_GREATER(N, 3)            \
                 , a3, BOOST_PP_EMPTY())                   \
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index b0ed98126..f59191885 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -164,6 +164,7 @@ if ! $(BOOST_ARCHIVE_LIST) {
         [ test-bsl-run test_iterators : : : [ requires std_wstreambuf ] ]
         [ test-bsl-run test_iterators_base64 ]
         [ test-bsl-run test_iterators_copy ]
+        [ test-bsl-run test_factory ]
         [ test-bsl-run test_smart_cast ]
         [ test-bsl-run test_codecvt_null ]
         [ test-bsl-run test_singleton ]
diff --git a/test/test_factory.cpp b/test/test_factory.cpp
new file mode 100644
index 000000000..d94111a2a
--- /dev/null
+++ b/test/test_factory.cpp
@@ -0,0 +1,108 @@
+/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
+// test_factory.cpp
+
+// Copyright 2026 Gennaro Prota.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+//  See http://www.boost.org for updates, documentation, and revision history.
+
+// BOOST_SERIALIZATION_FACTORY builds an object from the arguments an
+// extended_type_info was asked to construct it with.  Only the arity zero
+// form was ever used in the library, so the others went untested.
+
+// Reported by ivytin in
+// https://github.com/boostorg/serialization/issues/215: a misplaced
+// closing parenthesis kept every arity above zero from preprocessing at
+// all.  Thanks for spotting it, and for pinning down which parenthesis.
+
+// The arguments travel through a va_list, so they are limited to what
+// survives the default argument promotions.  A class type would not, which
+// is why the ones below are all int and double.
+
+#include <cstddef>
+#include <memory>
+
+#include <boost/config.hpp>
+#include <boost/serialization/extended_type_info_typeid.hpp>
+#include <boost/serialization/factory.hpp>
+#include <boost/serialization/singleton.hpp>
+
+#include "test_tools.hpp"
+
+struct arg0 {
+    arg0() : sum(0) {}
+    int sum;
+};
+
+struct arg1 {
+    explicit arg1(int a) : sum(a) {}
+    int sum;
+};
+
+struct arg2 {
+    arg2(int a, int b) : sum(a + b) {}
+    int sum;
+};
+
+struct arg3 {
+    arg3(int a, int b, int c) : sum(a + b + c) {}
+    int sum;
+};
+
+struct arg4 {
+    arg4(int a, int b, int c, double d)
+        : sum(a + b + c + static_cast<int>(d)) {}
+    int sum;
+};
+
+BOOST_SERIALIZATION_FACTORY_0(arg0)
+BOOST_SERIALIZATION_FACTORY_1(arg1, int)
+BOOST_SERIALIZATION_FACTORY_2(arg2, int, int)
+BOOST_SERIALIZATION_FACTORY_3(arg3, int, int, int)
+BOOST_SERIALIZATION_FACTORY_4(arg4, int, int, int, double)
+
+template<class T>
+static const boost::serialization::extended_type_info & eti_of(){
+    return boost::serialization::singleton<
+        boost::serialization::extended_type_info_typeid<T>
+    >::get_const_instance();
+}
+
+// construct() hands back a raw pointer it has just newed, so adopt it
+template<class T>
+static std::unique_ptr<T> owned(void * p){
+    return std::unique_ptr<T>(static_cast<T *>(p));
+}
+
+// construct() takes the count and then the arguments themselves, so the
+// factory is reached the way the library reaches it
+int
+test_main(int /* argc */, char * /* argv */ [])
+{
+    const std::unique_ptr<arg0> a0(owned<arg0>(eti_of<arg0>().construct(0)));
+    BOOST_REQUIRE(NULL != a0.get());
+    BOOST_CHECK(0 == a0->sum);
+
+    const std::unique_ptr<arg1> a1(owned<arg1>(eti_of<arg1>().construct(1, 7)));
+    BOOST_REQUIRE(NULL != a1.get());
+    BOOST_CHECK(7 == a1->sum);
+
+    const std::unique_ptr<arg2> a2(
+        owned<arg2>(eti_of<arg2>().construct(2, 7, 11)));
+    BOOST_REQUIRE(NULL != a2.get());
+    BOOST_CHECK(18 == a2->sum);
+
+    const std::unique_ptr<arg3> a3(
+        owned<arg3>(eti_of<arg3>().construct(3, 7, 11, 13)));
+    BOOST_REQUIRE(NULL != a3.get());
+    BOOST_CHECK(31 == a3->sum);
+
+    const std::unique_ptr<arg4> a4(
+        owned<arg4>(eti_of<arg4>().construct(4, 7, 11, 13, 2.0)));
+    BOOST_REQUIRE(NULL != a4.get());
+    BOOST_CHECK(33 == a4->sum);
+
+    return EXIT_SUCCESS;
+}