diff --git a/doc/manual.xml b/doc/manual.xml
index b046cb99f..227aa57dd 100644
--- a/doc/manual.xml
+++ b/doc/manual.xml
@@ -1524,7 +1524,7 @@ end;
         <synopfragment id="det_shock">
           <arg choice="plain">var <replaceable>VARIABLE_NAME</replaceable>;</arg>
           <arg choice="plain">periods <replaceable>INTEGER</replaceable><arg>:<replaceable>INTEGER</replaceable></arg><arg rep="repeat"><arg>,</arg> <replaceable>INTEGER</replaceable><arg>:<replaceable>INTEGER</replaceable></arg></arg>;</arg>
-          <arg choice="plain">values <replaceable>EXPRESSION</replaceable> <arg rep="repeat"><arg>,</arg> <replaceable>EXPRESSION</replaceable></arg>;</arg>
+          <arg choice="plain">values <group choice="plain"><arg choice="plain"><replaceable>DOUBLE</replaceable></arg><arg choice="plain">(<replaceable>EXPRESSION</replaceable>)</arg></group> <arg rep="repeat"><arg>,</arg> <group choice="plain"><arg choice="plain"><replaceable>DOUBLE</replaceable></arg><arg choice="plain">(<replaceable>EXPRESSION</replaceable>)</arg></group></arg>;</arg>
         </synopfragment>
 
         <synopfragment id="sto_shock">
@@ -1554,6 +1554,12 @@ end;
     will have a constant value over the range.
   </para>
 
+  <para>
+    Note that shock values are not restricted to numerical constants: arbitrary
+    expressions are also allowed, but you have to enclose them inside
+    parentheses.
+  </para>
+
   <refsect3><title>Example</title> 
   <informalexample>
     <programlisting>
@@ -1567,6 +1573,9 @@ values 0;
 var v;
 periods 4:5 6 7:9;
 values 1 1.1 0.9;
+var w;
+periods 1 2;
+values (1+p) (exp(z));
 end;
     </programlisting>
   </informalexample>
diff --git a/preprocessor/DynareBison.yy b/preprocessor/DynareBison.yy
index defb9cc97..bb88b3632 100644
--- a/preprocessor/DynareBison.yy
+++ b/preprocessor/DynareBison.yy
@@ -740,14 +740,19 @@ period_list : period_list COMMA INT_NUMBER
 
 sigma_e : SIGMA_E EQUAL '[' triangular_matrix ']' ';' { driver.do_sigma_e(); };
 
-value_list
- 	:  value_list COMMA expression
-    {driver.add_value($3);}
-  |  value_list number
-    {driver.add_value($2);}
-	| expression
-    {driver.add_value($1);}
-	;
+value_list : value_list COMMA '(' expression ')'
+             { driver.add_value($4); }
+           | value_list '(' expression ')'
+             { driver.add_value($3); }
+           | '(' expression ')'
+             { driver.add_value($2); }
+           | value_list COMMA signed_float
+             { driver.add_value($3); }
+           | value_list signed_float
+             { driver.add_value($2); }
+           | signed_float
+             { driver.add_value($1); }
+           ;
 
 triangular_matrix : triangular_matrix ';' triangular_row
                     { driver.end_of_row(); }
diff --git a/preprocessor/ParsingDriver.cc b/preprocessor/ParsingDriver.cc
index a719334af..e3eb96a54 100644
--- a/preprocessor/ParsingDriver.cc
+++ b/preprocessor/ParsingDriver.cc
@@ -700,9 +700,15 @@ ParsingDriver::add_value(expr_t value)
 }
 
 void
-ParsingDriver::add_value(string *p1)
+ParsingDriver::add_value(string *v)
 {
-  det_shocks_values.push_back(add_constant(p1));
+  expr_t id;
+  if (v->at(0) == '-')
+    id = data_tree->AddUMinus(data_tree->AddNumConstant(v->substr(1, string::npos)));
+  else
+    id = data_tree->AddNumConstant(*v);
+  delete v;
+  det_shocks_values.push_back(id);
 }
 
 void
diff --git a/preprocessor/ParsingDriver.hh b/preprocessor/ParsingDriver.hh
index 32147ee21..a84cf240c 100644
--- a/preprocessor/ParsingDriver.hh
+++ b/preprocessor/ParsingDriver.hh
@@ -283,7 +283,8 @@ public:
   //! Adds a deterministic shock value
   void add_value(expr_t value);
   //! Adds a deterministic shock value
-  void add_value(string *p1);
+  /*! \param v a string containing a (possibly negative) numeric constant */
+  void add_value(string *v);
   //! Writes a Sigma_e block
   void do_sigma_e();
   //! Ends row of Sigma_e block