diff --git a/src/DynareBison.yy b/src/DynareBison.yy
index fa7ee5d4d865c6744fd291bde5a3111eff90fc41..deabedfa3922ddeddabae1dc95d9d56125a348d2 100644
--- a/src/DynareBison.yy
+++ b/src/DynareBison.yy
@@ -173,7 +173,8 @@ str_tolower(string s)
 %token VLISTLOG VLISTPER SPECTRAL_DENSITY INIT2SHOCKS
 %token RESTRICTION RESTRICTION_FNAME CROSS_RESTRICTIONS NLAGS CONTEMP_REDUCED_FORM REAL_PSEUDO_FORECAST
 %token DUMMY_OBS NSTATES INDXSCALESSTATES NO_BAYESIAN_PRIOR SPECIFICATION SIMS_ZHA
-%token <string> ALPHA BETA ABAND NINV CMS NCMS CNUM GAMMA INV_GAMMA INV_GAMMA1 INV_GAMMA2 NORMAL UNIFORM EPS PDF FIG DR NONE PRIOR PRIOR_VARIANCE HESSIAN IDENTITY_MATRIX DIRICHLET DIAGONAL OPTIMAL MFS RESIDUAL
+%token <string> ALPHA BETA ABAND NINV CMS NCMS CNUM GAMMA INV_GAMMA INV_GAMMA1 INV_GAMMA2 NORMAL UNIFORM EPS PDF FIG DR NONE PRIOR DIRICHLET MFS RESIDUAL
+%token PRIOR_VARIANCE HESSIAN IDENTITY_MATRIX
 %token GSIG2_LMDM Q_DIAG FLAT_PRIOR NCSK NSTD WEIBULL WEIBULL_PDF
 %token INDXPARR INDXOVR INDXAP APBAND INDXIMF INDXFORE FOREBAND INDXGFOREHAT INDXGIMFHAT
 %token INDXESTIMA INDXGDLS EQ_MS FILTER_COVARIANCE UPDATED_COVARIANCE FILTER_DECOMPOSITION SMOOTHED_STATE_UNCERTAINTY SMOOTHER_REDUX
@@ -4354,10 +4355,11 @@ o_analytic_derivation_mode : ANALYTIC_DERIVATION_MODE EQUAL signed_number { driv
 o_endogenous_prior : ENDOGENOUS_PRIOR { driver.option_num("endogenous_prior", "true"); }
 o_use_univariate_filters_if_singularity_is_detected : USE_UNIVARIATE_FILTERS_IF_SINGULARITY_IS_DETECTED EQUAL INT_NUMBER { driver.option_num("use_univariate_filters_if_singularity_is_detected", $3); }
 o_mcmc_jumping_covariance : MCMC_JUMPING_COVARIANCE EQUAL HESSIAN
-                            { driver.option_str("MCMC_jumping_covariance", $3); }                                  | MCMC_JUMPING_COVARIANCE EQUAL PRIOR_VARIANCE
-                            { driver.option_str("MCMC_jumping_covariance", $3); }
+                            { driver.option_str("MCMC_jumping_covariance", "hessian"); }
+                          | MCMC_JUMPING_COVARIANCE EQUAL PRIOR_VARIANCE
+                            { driver.option_str("MCMC_jumping_covariance", "prior_variance"); }
                           | MCMC_JUMPING_COVARIANCE EQUAL IDENTITY_MATRIX
-                            { driver.option_str("MCMC_jumping_covariance", $3); }
+                            { driver.option_str("MCMC_jumping_covariance", "identity_matrix"); }
                           | MCMC_JUMPING_COVARIANCE EQUAL filename
                             { driver.option_str("MCMC_jumping_covariance", $3); }
                           ;
diff --git a/src/DynareFlex.ll b/src/DynareFlex.ll
index 85f0c9f5dc9fe2eeaa5b97747f1e248ea2ac1e88..8574a94cb0481bfee6f1e7afefde00c308e1c8cf 100644
--- a/src/DynareFlex.ll
+++ b/src/DynareFlex.ll
@@ -471,10 +471,7 @@ DATE -?[0-9]+([ya]|m([1-9]|1[0-2])|q[1-4]|[sh][12])
   yylval->emplace<string>(yytext);
   return token::DIRICHLET;
 }
-<DYNARE_STATEMENT>weibull {
-  yylval->emplace<string>(yytext);
-  return token::WEIBULL;
-}
+<DYNARE_STATEMENT>weibull {return token::WEIBULL;}
 <DYNARE_STATEMENT>normal {
   yylval->emplace<string>(yytext);
   return token::NORMAL;
@@ -607,18 +604,9 @@ DATE -?[0-9]+([ya]|m([1-9]|1[0-2])|q[1-4]|[sh][12])
 <DYNARE_STATEMENT>substitute_libs {return token::SUBSTITUTE_LIBS;}
 <DYNARE_STATEMENT>compiler {return token::COMPILER;}
 <DYNARE_STATEMENT>instruments {return token::INSTRUMENTS;}
-<DYNARE_STATEMENT>hessian  {
-  yylval->emplace<string>(yytext);
-  return token::HESSIAN;
-}
-<DYNARE_STATEMENT>prior_variance  {
-  yylval->emplace<string>(yytext);
-  return token::PRIOR_VARIANCE;
-}
-<DYNARE_STATEMENT>identity_matrix  {
-  yylval->emplace<string>(yytext);
-  return token::IDENTITY_MATRIX;
-}
+<DYNARE_STATEMENT>hessian  {return token::HESSIAN;}
+<DYNARE_STATEMENT>prior_variance  {return token::PRIOR_VARIANCE;}
+<DYNARE_STATEMENT>identity_matrix  {return token::IDENTITY_MATRIX;}
 <DYNARE_STATEMENT>mcmc_jumping_covariance {return token::MCMC_JUMPING_COVARIANCE;}
 
  /* These four (var, varexo, varexo_det, parameters) are for change_type */
@@ -718,14 +706,6 @@ DATE -?[0-9]+([ya]|m([1-9]|1[0-2])|q[1-4]|[sh][12])
 <DYNARE_STATEMENT>lmmcp {return token::LMMCP;}
 <DYNARE_STATEMENT>additional_optimizer_steps	{return token::ADDITIONAL_OPTIMIZER_STEPS;}
 <DYNARE_STATEMENT>bartlett_kernel_lag {return token::BARTLETT_KERNEL_LAG; }
-<DYNARE_STATEMENT>optimal {
-  yylval->emplace<string>(yytext);
-  return token::OPTIMAL;
-}
-<DYNARE_STATEMENT>diagonal  {
-  yylval->emplace<string>(yytext);
-  return token::DIAGONAL;
-}
 <DYNARE_STATEMENT>gmm {return token::GMM;}
 <DYNARE_STATEMENT>smm {return token::SMM;}
 <DYNARE_STATEMENT>irf_matching {return token::IRF_MATCHING;}