diff --git a/ion/src/shared/unicode/utf8_decoder.cpp b/ion/src/shared/unicode/utf8_decoder.cpp
index 73ef028a1..a91895417 100644
--- a/ion/src/shared/unicode/utf8_decoder.cpp
+++ b/ion/src/shared/unicode/utf8_decoder.cpp
@@ -52,7 +52,7 @@ CodePoint UTF8Decoder::previousCodePoint() {
   assert(leadingOnes > 1 && leadingOnes <= 4);
   assert(m_stringPosition >= m_string);
 
-  result+= last_k_bits(*m_stringPosition, 8-leadingOnes-1);
+  result+= last_k_bits(*m_stringPosition, 8-leadingOnes-1) << (6*i);
   return CodePoint(result);
 }