Hong Kong Special Administrative Region of the People's Republic of China
Bank of China (Hong Kong Branch)
These are two uncut sheets of three $100 notes issued in 2017 celebrating the bank's 100th year of establishment in Hong Kong 1917-2017. The sheets below are printed with no letters prefix and with AA prefix. Other prefixes such as AB, BC, HK and HY are also issued. If you collect all prefixes for this issue then a complete set should be 6 pieces. Lucky you if you have them all.
In my opinion, I do not believe the bank had printed any replacement prefix, however I can't explain why they have printed prefixes like AA, AB and HY. It would be logical to have AA and AB prefixes but why HY? What is HY stands for?
One Hundred Dollars