diff --git a/src/formula/BoundedUntil.h b/src/formula/BoundedUntil.h
index e00acac74..cf222c588 100644
--- a/src/formula/BoundedUntil.h
+++ b/src/formula/BoundedUntil.h
@@ -148,13 +148,11 @@ public:
 	 * @returns a string representation of the formula
 	 */
 	virtual std::string toString() const {
-		std::string result = "(";
-		result += left->toString();
+		std::string result = left->toString();
 		result += " U<=";
 		result += std::to_string(bound);
 		result += " ";
 		result += right->toString();
-		result += ")";
 		return result;
 	}
 
diff --git a/src/formula/Until.h b/src/formula/Until.h
index 82ac05c9d..543a4febd 100644
--- a/src/formula/Until.h
+++ b/src/formula/Until.h
@@ -125,11 +125,9 @@ public:
 	 * @returns a string representation of the formula
 	 */
 	virtual std::string toString() const {
-		std::string result = "(";
-		result += left->toString();
+		std::string result = left->toString();
 		result += " U ";
 		result += right->toString();
-		result += ")";
 		return result;
 	}
 
diff --git a/test/parser/PrctlParserTest.cpp b/test/parser/PrctlParserTest.cpp
index 02d9ddc43..35db62575 100644
--- a/test/parser/PrctlParserTest.cpp
+++ b/test/parser/PrctlParserTest.cpp
@@ -77,7 +77,7 @@ TEST(PrctlParserTest, parseRewardFormulaTest) {
 	ASSERT_EQ(storm::formula::BoundOperator<double>::GREATER_EQUAL, op->getComparisonOperator());
 	ASSERT_EQ(15.0, op->getBound());
 
-	ASSERT_EQ(prctlFileParser->getFormula()->toString(), "R >= 15.000000 [(a U !b)]");
+	ASSERT_EQ(prctlFileParser->getFormula()->toString(), "R >= 15.000000 [a U !b]");
 
 	delete prctlFileParser->getFormula();
 	delete prctlFileParser;
@@ -92,7 +92,7 @@ TEST(PrctlParserTest, parseRewardNoBoundFormulaTest) {
 	ASSERT_NE(prctlFileParser->getFormula(), nullptr);
 
 
-	ASSERT_EQ(prctlFileParser->getFormula()->toString(), "R = ? [(a U<=4 (b & !c))]");
+	ASSERT_EQ(prctlFileParser->getFormula()->toString(), "R = ? [a U<=4 (b & !c)]");
 
 	delete prctlFileParser->getFormula();
 	delete prctlFileParser;