The Bank of Thailand is offering commemorative 500,000-baht banknotes for 1 million baht each at the Money Expo underway at Impact Muang Thong Thani.
Central bank spokesman Jirathep Seneewongse na Ayudhya said the bills were issued to commemorate the 50th anniversary of the wedding of Their Majesties the the King and Queen on April 28, 2000.
There were 1,998 banknotes printed and they were first distributed to the public on May 5, 2000.
The BOT was asked by the fair organiser to exhibit the special banknote at the BoT's booth, said Mr Jirathep.
He said there were a significant number of banknotes still available for the public to purchase at 1 million baht each.
According to the central bank's website, there are 235 500,000-baht banknotes in circulation.