diff --git a/preprocessor/DynareFlex.ll b/preprocessor/DynareFlex.ll
index c836be7f7..a5a3f6d73 100644
--- a/preprocessor/DynareFlex.ll
+++ b/preprocessor/DynareFlex.ll
@@ -690,7 +690,7 @@ string eofbuff;
   return token::INT_NUMBER;
 }
 
-<DYNARE_STATEMENT,DYNARE_BLOCK>dates[[:space:]]*\([[:space:]]*\'[[:space:]]*-?[0-9]+([YyAa]|[Mm]([1-9]|1[0-2])|[Qq][1-4]|[Ww]([1-9]{1}|[1-4][0-9]|5[0-2]))[[:space:]]*\'[[:space:]]*\) {
+<DYNARE_STATEMENT,DYNARE_BLOCK>dates[[:space:]]*\([[:space:]]*\'[[:space:]]*(-[1-9][0-9]*|[0-9]+)([YyAa]|[Mm]([1-9]|1[0-2])|[Qq][1-4]|[Ww]([1-9]{1}|[1-4][0-9]|5[0-2]))[[:space:]]*\'[[:space:]]*\) {
   yylval->string_val = new string(yytext);
   return token::DATE_NUMBER;
 }
diff --git a/preprocessor/macro/MacroFlex.ll b/preprocessor/macro/MacroFlex.ll
index 792efce71..9235cf3b5 100644
--- a/preprocessor/macro/MacroFlex.ll
+++ b/preprocessor/macro/MacroFlex.ll
@@ -61,7 +61,7 @@ typedef Macro::parser::token token;
 SPC  [ \t]+
 EOL  (\r)?\n
 CONT \\\\
-DATE -?[0-9]+([YyAa]|[Mm]([1-9]|1[0-2])|[Qq][1-4]|[Ww]([1-9]{1}|[1-4][0-9]|5[0-2]))
+DATE (-[1-9][0-9]*|[0-9]+)([YyAa]|[Mm]([1-9]|1[0-2])|[Qq][1-4]|[Ww]([1-9]{1}|[1-4][0-9]|5[0-2]))
 
 %%
  /* Code put at the beginning of yylex() */