diff --git a/lib/mu-parser.cc b/lib/mu-parser.cc
index 3cde7c5f..de6cc543 100644
--- a/lib/mu-parser.cc
+++ b/lib/mu-parser.cc
@@ -267,7 +267,7 @@ Parser::Private::regex(const FieldInfoVec& fields,
 		for (const auto& field : fields) {
 			const auto terms = process_regex(field.field, rx);
 			for (const auto& term : terms) {
-				tree.add_child(Tree({Node::Type::Value,
+				tree.add_child(Tree({Node::Type::ValueAtomic,
 							FieldValue{field.id, term}}));
 			}
 		}
diff --git a/lib/mu-tree.hh b/lib/mu-tree.hh
index ce9093c8..5c058905 100644
--- a/lib/mu-tree.hh
+++ b/lib/mu-tree.hh
@@ -80,6 +80,7 @@ struct Node {
 		OpAndNot,
 		OpNot,
 		Value,
+                ValueAtomic,
 		Range,
 		Invalid
 	};
@@ -107,6 +108,8 @@ struct Node {
 			return "not";
 		case Type::Value:
 			return "value";
+		case Type::ValueAtomic:
+			return "value_atomic";
 		case Type::Range:
 			return "range";
 		case Type::Invalid:
diff --git a/lib/mu-xapian.cc b/lib/mu-xapian.cc
index 829667c1..19b3d3c3 100644
--- a/lib/mu-xapian.cc
+++ b/lib/mu-xapian.cc
@@ -83,11 +83,15 @@ xapian_query_value(const Mu::Tree& tree)
 		return make_query(field_val, true /*maybe-wildcard*/);
 	}
 
+        const bool is_atomic = tree.node.type == Node::Type::ValueAtomic;
+
 	const auto parts{split(field_val.value(), " ")};
 	if (parts.empty())
 		return Xapian::Query::MatchNothing; // shouldn't happen
-	else if (parts.size() == 1)
+	else if (parts.size() == 1 && !is_atomic)
 		return make_query(field_val, true /*maybe-wildcard*/);
+        else if (is_atomic)
+                return make_query(field_val, false /*maybe-wildcard*/);
 
 	std::vector<Xapian::Query> phvec;
 	for (const auto& p : parts) {
@@ -124,6 +128,7 @@ Mu::xapian_query(const Mu::Tree& tree)
 	case Node::Type::OpAndNot:
 		return xapian_query_op(tree);
 	case Node::Type::Value:
+	case Node::Type::ValueAtomic:
 		return xapian_query_value(tree);
 	case Node::Type::Range:
 		return xapian_query_range(tree);