diff --git a/src/stan/services/sample/hmc_nuts_dense_e.hpp b/src/stan/services/sample/hmc_nuts_dense_e.hpp
index 0fb818b19c..457f7483c1 100644
--- a/src/stan/services/sample/hmc_nuts_dense_e.hpp
+++ b/src/stan/services/sample/hmc_nuts_dense_e.hpp
@@ -237,7 +237,7 @@ int hmc_nuts_dense_e(Model& model, size_t num_chains,
             util::run_sampler(samplers[i], model, cont_vectors[i], num_warmup,
                               num_samples, num_thin, refresh, save_warmup,
                               rngs[i], interrupt, logger, sample_writer[i],
-                              diagnostic_writer[i], init_chain_id + i);
+                              diagnostic_writer[i], init_chain_id + i, num_chains);
           }
         },
         tbb::simple_partitioner());
diff --git a/src/stan/services/sample/hmc_nuts_diag_e.hpp b/src/stan/services/sample/hmc_nuts_diag_e.hpp
index bb789c0151..94fd66c748 100644
--- a/src/stan/services/sample/hmc_nuts_diag_e.hpp
+++ b/src/stan/services/sample/hmc_nuts_diag_e.hpp
@@ -232,7 +232,7 @@ int hmc_nuts_diag_e(Model& model, size_t num_chains,
           util::run_sampler(samplers[i], model, cont_vectors[i], num_warmup,
                             num_samples, num_thin, refresh, save_warmup,
                             rngs[i], interrupt, logger, sample_writer[i],
-                            diagnostic_writer[i], init_chain_id + i);
+                            diagnostic_writer[i], init_chain_id + i, num_chains);
         }
       },
       tbb::simple_partitioner());