diff --git a/semantica/normalize/number_normalizer.py b/semantica/normalize/number_normalizer.py
index f7876b7c..29911cb9 100644
--- a/semantica/normalize/number_normalizer.py
+++ b/semantica/normalize/number_normalizer.py
@@ -562,6 +562,11 @@ def __init__(self, **config):
             "SEK",
             "NOK",
             "DKK",
+            "RUB",
+            "KRW",
+            "ILS",
+            "NGN",
+            "PKR",
         ]
 
         self.logger.debug("Currency normalizer initialized")
@@ -606,13 +611,15 @@ def normalize_currency(
         # Check for currency code
         if not currency_code:
             for code in self.currency_codes:
-                if code in currency_input.upper():
+                match = re.search(
+                    rf"(?<![A-Z]){re.escape(code)}(?![A-Z])",
+                    currency_input.upper(),
+                )
+                if match:
                     currency_code = code
                     amount_str = (
-                        currency_input.replace(code, "")
-                        .replace(code.lower(), "")
-                        .strip()
-                    )
+                        currency_input[: match.start()] + currency_input[match.end() :]
+                    ).strip()
                     amount_str = amount_str.replace(",", "").replace(" ", "")
                     try:
                         amount = float(amount_str)
diff --git a/tests/normalize/test_number_normalizer.py b/tests/normalize/test_number_normalizer.py
index 8af84eca..a7cf359c 100644
--- a/tests/normalize/test_number_normalizer.py
+++ b/tests/normalize/test_number_normalizer.py
@@ -49,6 +49,24 @@ def test_parse_currency(self):
         self.assertEqual(result["amount"], 100.0)
         self.assertEqual(result["currency"], "EUR")
 
+    def test_symbol_currencies_are_validated_as_supported_codes(self):
+        for symbol, expected_code in self.normalizer.currency_symbols.items():
+            result = self.normalizer.normalize_currency(f"{symbol}100")
+            self.assertEqual(result["currency"], expected_code)
+            self.assertTrue(self.normalizer.validate_currency_code(result["currency"]))
+
+    def test_currency_codes_match_boundaries_without_matching_words(self):
+        for value in ("RUB100", "100 RUB", "rub 100"):
+            result = self.normalizer.normalize_currency(value)
+            self.assertEqual(result["amount"], 100.0)
+            self.assertEqual(result["currency"], "RUB")
+
+        for value in ("ruby 100", "wilson 100"):
+            result = self.normalizer.normalize_currency(value)
+            self.assertEqual(result["amount"], 100.0)
+            self.assertEqual(result["currency"], "USD")
+
+
 class TestScientificNotationHandler(unittest.TestCase):
     def setUp(self):
         self.handler = ScientificNotationHandler()