diff --git a/src/collection.cpp b/src/collection.cpp
index 4414b39d..3ab0fe25 100644
--- a/src/collection.cpp
+++ b/src/collection.cpp
@@ -2232,7 +2232,7 @@ Option<bool> Collection::parse_filter_query(const std::string& simple_filter_que
                 // string filter should be evaluated in strict "equals" mode
                 str_comparator = EQUALS;
                 while(raw_value[++filter_value_index] == ' ');
-            } else if(raw_value[0] == '-') {
+            } else if(raw_value.size() >= 2 && raw_value[0] == '!' && raw_value[1] == '=') {
                 if(!_field.facet) {
                     // EXCLUDE filtering on string is possible only on facet fields
                     return Option<bool>(400, "To perform exclude filtering, filter field `" +
diff --git a/test/collection_filtering_test.cpp b/test/collection_filtering_test.cpp
index 0602ae05..30cc9a20 100644
--- a/test/collection_filtering_test.cpp
+++ b/test/collection_filtering_test.cpp
@@ -1323,7 +1323,7 @@ TEST_F(CollectionFilteringTest, NegationOperatorBasics) {
         ASSERT_TRUE(coll1->add(doc.dump()).ok());
     }
 
-    auto results = coll1->search("*", {"artist"}, "artist:- Michael Jackson", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
+    auto results = coll1->search("*", {"artist"}, "artist:!= Michael Jackson", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
 
     ASSERT_EQ(3, results["found"].get<size_t>());
 
@@ -1331,14 +1331,14 @@ TEST_F(CollectionFilteringTest, NegationOperatorBasics) {
     ASSERT_STREQ("2", results["hits"][1]["document"]["id"].get<std::string>().c_str());
     ASSERT_STREQ("0", results["hits"][2]["document"]["id"].get<std::string>().c_str());
 
-    results = coll1->search("*", {"artist"}, "artist:- Michael Jackson && points: >0", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
+    results = coll1->search("*", {"artist"}, "artist:!= Michael Jackson && points: >0", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
     ASSERT_EQ(2, results["found"].get<size_t>());
     ASSERT_STREQ("3", results["hits"][0]["document"]["id"].get<std::string>().c_str());
     ASSERT_STREQ("2", results["hits"][1]["document"]["id"].get<std::string>().c_str());
 
     // negation operation on multiple values
 
-    results = coll1->search("*", {"artist"}, "artist:- [Michael Jackson, Taylor Swift]", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
+    results = coll1->search("*", {"artist"}, "artist:!= [Michael Jackson, Taylor Swift]", {}, {}, {0}, 10, 1, FREQUENCY, {true}, 10).get();
     ASSERT_EQ(1, results["found"].get<size_t>());
     ASSERT_STREQ("3", results["hits"][0]["document"]["id"].get<std::string>().c_str());