diff --git a/src/middle/Stan_math_signatures.ml b/src/middle/Stan_math_signatures.ml
index 290a005712..e8cba5d7cf 100644
--- a/src/middle/Stan_math_signatures.ml
+++ b/src/middle/Stan_math_signatures.ml
@@ -1706,6 +1706,7 @@ let () =
   add_unqualified ("sum", ReturnType UReal, [UMatrix]) ;
   add_unqualified ("svd_U", ReturnType UMatrix, [UMatrix]) ;
   add_unqualified ("svd_V", ReturnType UMatrix, [UMatrix]) ;
+  add_unqualified ("symmetrize_from_lower_tri", ReturnType UMatrix, [UMatrix]) ;
   add_unqualified ("tail", ReturnType URowVector, [URowVector; UInt]) ;
   add_unqualified ("tail", ReturnType UVector, [UVector; UInt]) ;
   List.iter
diff --git a/test/integration/good/code-gen/cpp.expected b/test/integration/good/code-gen/cpp.expected
index 33d68199b1..a08fd4dd12 100644
--- a/test/integration/good/code-gen/cpp.expected
+++ b/test/integration/good/code-gen/cpp.expected
@@ -20209,7 +20209,8 @@ using stan::model::nil_index_list;
 using namespace stan::math;
 using stan::math::pow; 
 
-static int current_statement__ = 0;
+stan::math::profile_map profiles__;
+static int current_statement__= 0;
 static const std::vector<string> locations_array__ = {" (found before start of program)",
                                                       " (in 'param-constraint.stan', line 7, column 2 to column 38)",
                                                       " (in 'param-constraint.stan', line 8, column 2 to column 38)",
@@ -20713,6 +20714,10 @@ stan::model::model_base& new_model(
   return *m;
 }
 
+stan::math::profile_map& get_stan_profile_data() {
+  return param_constraint_model_namespace::profiles__;
+}
+
 #endif
 
 
diff --git a/test/integration/good/function-signatures/math/matrix/pretty.expected b/test/integration/good/function-signatures/math/matrix/pretty.expected
index 70527f47fc..7b9ebf06a2 100644
--- a/test/integration/good/function-signatures/math/matrix/pretty.expected
+++ b/test/integration/good/function-signatures/math/matrix/pretty.expected
@@ -19465,6 +19465,28 @@ transformed parameters {
   transformed_param_matrix = svd_V(d_matrix);
   transformed_param_matrix = svd_V(p_matrix);
 }
+model {
+  y_p ~ normal(0, 1);
+}
+
+  $ ../../../../../../../install/default/bin/stanc --auto-format symmetrize_from_lower_tri.stan
+data {
+  int d_int;
+  matrix[d_int, d_int] d_matrix;
+}
+transformed data {
+  matrix[d_int, d_int] transformed_data_matrix;
+  transformed_data_matrix = symmetrize_from_lower_tri(d_matrix);
+}
+parameters {
+  real y_p;
+  matrix[d_int, d_int] p_matrix;
+}
+transformed parameters {
+  matrix[d_int, d_int] transformed_param_matrix;
+  transformed_param_matrix = symmetrize_from_lower_tri(d_matrix);
+  transformed_param_matrix = symmetrize_from_lower_tri(p_matrix);
+}
 model {
   y_p ~ normal(0, 1);
 }
diff --git a/test/integration/good/function-signatures/math/matrix/symmetrize_from_lower_tri.stan b/test/integration/good/function-signatures/math/matrix/symmetrize_from_lower_tri.stan
new file mode 100644
index 0000000000..c222b6888b
--- /dev/null
+++ b/test/integration/good/function-signatures/math/matrix/symmetrize_from_lower_tri.stan
@@ -0,0 +1,23 @@
+data { 
+  int d_int;
+  matrix[d_int,d_int] d_matrix;
+}
+
+transformed data {
+  matrix[d_int,d_int] transformed_data_matrix;
+
+  transformed_data_matrix = symmetrize_from_lower_tri(d_matrix);
+}
+parameters {
+  real y_p;
+  matrix[d_int,d_int] p_matrix;
+}
+transformed parameters {
+  matrix[d_int,d_int] transformed_param_matrix;
+
+  transformed_param_matrix = symmetrize_from_lower_tri(d_matrix);
+  transformed_param_matrix = symmetrize_from_lower_tri(p_matrix);
+}
+model {  
+  y_p ~ normal(0,1);
+}
diff --git a/test/integration/signatures/stan_math_sigs.expected b/test/integration/signatures/stan_math_sigs.expected
index ee8c2e23ad..ed1e605edc 100644
--- a/test/integration/signatures/stan_math_sigs.expected
+++ b/test/integration/signatures/stan_math_sigs.expected
@@ -23503,6 +23503,7 @@ real sum(matrix)
 real sum(real[])
 matrix svd_U(matrix)
 matrix svd_V(matrix)
+matrix symmetrize_from_lower_tri(matrix)
 vector tail(vector, int)
 row_vector tail(row_vector, int)
 int[] tail(int[], int)