diff --git a/preprocessor/DynareBison.yy b/preprocessor/DynareBison.yy
index 3b86f4c475b29bb3f05a45b776af6bd1aa8f92b3..8fe2d41b91ee43b7268155b940f742e23e51c289 100644
--- a/preprocessor/DynareBison.yy
+++ b/preprocessor/DynareBison.yy
@@ -145,7 +145,7 @@ class ParsingDriver;
 %token FREQ INITIAL_YEAR INITIAL_SUBPERIOD FINAL_YEAR FINAL_SUBPERIOD DATA VLIST VARLIST LOG_VAR PERCENT_VAR
 %token VLISTLOG VLISTPER
 %token RESTRICTIONS RESTRICTION_FNAME CROSS_RESTRICTIONS NLAGS CONTEMP_REDUCED_FORM REAL_PSEUDO_FORECAST 
-%token DUMMY_OBS NSTATES INDXSCALESSTATES BAYESIAN_PRIOR
+%token DUMMY_OBS NSTATES INDXSCALESSTATES NO_BAYESIAN_PRIOR
 %token <string_val> ALPHA BETA ABAND NINV CMS NCMS CNUM
 %token GSIG2_LMD GSIG2_LMDM Q_DIAG FLAT_PRIOR NCSK NSTD
 %token INDXPARR INDXOVR INDXAP APBAND INDXIMF IMFBAND INDXFORE FOREBAND INDXGFOREHAT INDXGIMFHAT
@@ -1436,7 +1436,7 @@ sbvar_option : o_datafile
              | o_cross_restrictions
              | o_contemp_reduced_form
              | o_real_pseudo_forecast
-             | o_bayesian_prior
+             | o_no_bayesian_prior
              | o_dummy_obs
              | o_nstates
              | o_indxscalesstates
@@ -1625,7 +1625,7 @@ ms_estimation_option : o_coefficients_prior_hyperparameters
                      | o_nlags
                      | o_cross_restrictions
                      | o_contemp_reduced_form
-                     | o_bayesian_prior
+                     | o_no_bayesian_prior
                      | o_alpha
                      | o_beta
                      | o_gsig2_lmd
@@ -2011,7 +2011,7 @@ o_nlags : NLAGS EQUAL INT_NUMBER {driver.option_num("ms.nlags",$3); };
 o_cross_restrictions : CROSS_RESTRICTIONS {driver.option_num("ms.cross_restrictions","1"); };
 o_contemp_reduced_form : CONTEMP_REDUCED_FORM {driver.option_num("ms.contemp_reduced_form","1"); };
 o_real_pseudo_forecast : REAL_PSEUDO_FORECAST EQUAL INT_NUMBER {driver.option_num("ms.real_pseudo_forecast",$3); };
-o_bayesian_prior : BAYESIAN_PRIOR EQUAL INT_NUMBER {driver.option_num("ms.bayesian_prior",$3); };
+o_no_bayesian_prior : NO_BAYESIAN_PRIOR {driver.option_num("ms.bayesian_prior","0"); };
 o_dummy_obs : DUMMY_OBS EQUAL INT_NUMBER {driver.option_num("ms.dummy_obs",$3); };
 o_nstates : NSTATES EQUAL INT_NUMBER {driver.option_num("ms.nstates",$3); };
 o_indxscalesstates : INDXSCALESSTATES EQUAL INT_NUMBER {driver.option_num("ms.indxscalesstates",$3); };
diff --git a/preprocessor/DynareFlex.ll b/preprocessor/DynareFlex.ll
index bc30e7a0195bdf30c980780c522125cd6aea212a..fccdf4075d0c9766aba5e6e27cabed07ee84d37e 100644
--- a/preprocessor/DynareFlex.ll
+++ b/preprocessor/DynareFlex.ll
@@ -263,7 +263,7 @@ string eofbuff;
 <DYNARE_STATEMENT>cross_restrictions {return token::CROSS_RESTRICTIONS;}
 <DYNARE_STATEMENT>contemp_reduced_form {return token::CONTEMP_REDUCED_FORM;}
 <DYNARE_STATEMENT>real_pseudo_forecast {return token::REAL_PSEUDO_FORECAST;}
-<DYNARE_STATEMENT>bayesian_prior {return token::BAYESIAN_PRIOR;}
+<DYNARE_STATEMENT>no_bayesian_prior {return token::NO_BAYESIAN_PRIOR;}
 <DYNARE_STATEMENT>dummy_obs {return token::DUMMY_OBS;}
 <DYNARE_STATEMENT>nstates {return token::NSTATES;}
 <DYNARE_STATEMENT>indxscalesstates {return token::INDXSCALESSTATES;}