diff --git a/lib/sec_id/cusip.rb b/lib/sec_id/cusip.rb
index 2631ebb..6fad6f7 100644
--- a/lib/sec_id/cusip.rb
+++ b/lib/sec_id/cusip.rb
@@ -35,6 +35,11 @@ def to_isin(country_code)
       isin
     end
 
+    # CUSIP International Numbering System
+    def cins?
+      !cusip6[0].match?(/[0-9]/)
+    end
+
     private
 
     # https://en.wikipedia.org/wiki/Luhn_algorithm
diff --git a/spec/sec_id/cusip_spec.rb b/spec/sec_id/cusip_spec.rb
index 9910f03..7a651a3 100644
--- a/spec/sec_id/cusip_spec.rb
+++ b/spec/sec_id/cusip_spec.rb
@@ -89,6 +89,24 @@
     end
   end
 
+  describe '#cins?' do
+    context 'when a CINS' do
+      let(:cusip_number) { 'G0052B105' }
+
+      it 'returns true' do
+        expect(cusip.cins?).to be(true)
+      end
+    end
+
+    context 'when not a CINS' do
+      let(:cusip_number) { '084664BL4' }
+
+      it 'returns false' do
+        expect(cusip.cins?).to be(false)
+      end
+    end
+  end
+
   describe '.restore!' do
     context 'when CUSIP is incorrect' do
       it 'raises an error' do