The Bank of Japan said Wednesday it suspects one of its employees stole commemorative gold coins worth about 1.55 million yen ($14,400) from its head office in Tokyo.
The central bank said in a statement that it moved the employee out of the relevant section and filed a police report the same day.
According to the BOJ, a regular check of a vault on April 10 revealed that a 50,000-yen coin issued to commemorate the 1993 marriage of Crown Prince Naruhito and Crown Princess Masako was missing.
Further inspections found that 16 coins, including some 100,000-yen pieces issued in 1990 to commemorate Emperor Akihito's accession to the throne the year prior, were also gone.
After interviewing staff and inspecting its own records, the bank determined there is a high possibility that the coins were removed by an employee within the Nihombashi Currency Issue Division, part of its Currency Issue Department.
The bank said it plans to discipline the employee in question and others as soon as it fully confirms the facts.
It offered an apology to the public, saying in the statement that it "is taking this misconduct extremely seriously.