diff --git a/gtsam/linear/IterativeOptimizationParameters.h b/gtsam/linear/IterativeOptimizationParameters.h
index 6c541ea21..b717d9c3e 100644
--- a/gtsam/linear/IterativeOptimizationParameters.h
+++ b/gtsam/linear/IterativeOptimizationParameters.h
@@ -118,7 +118,8 @@ struct ConjugateGradientParameters {
 
   enum BLASKernel {   /* Matrix Operation Kernel */
     GTSAM = 0,        /* Jacobian Factor Graph of GTSAM */
-    SBM               /* Sparse Block Matrix */
+    SBM,              /* Sparse Block Matrix */
+    SBM_MT            /* Sparse Block Matrix Multithreaded */
   } blas_kernel_;
 
   size_t degree_;         /* the maximum degree of the vertices to be eliminated before doing cg */