Tokyo police arrested on Tuesday a 46-year old former employee of MUFG Bank for allegedly stealing gold ingots worth ¥260 million from customers’ safe deposit boxes. The case has raised concerns about the security of deposit boxes and the potential impact on the bank’s trustworthiness.

Yukari Imamura, who has admitted to the allegations, is suspected of stealing about 20 kilograms of gold ingots that belonged to two clients of the Nerima branch in Tokyo last September.

At least 60 clients have been victims of the safe deposit box thefts linked to Imamura, with the total damage expected to exceed ¥1 billion, according to the bank's probe.

Imamura is believed to have exchanged the ingots for cash at several pawn shops and spent the money mainly on investments.

Imamura has told police investigators that she lost money on foreign exchange margin trading and betting on horse races and that she had a lot of debt, according to people familiar with the investigation.

She was in sole charge of managing safe deposit boxes at the bank's Nerima and Tamagawa branches in Tokyo between April 2020 and October 2024, MUFG Bank said.

She is believed to have illicitly opened safe deposit boxes to steal cash and other goods using keys kept at the branches.

The bank's safe deposit boxes are opened using both the client's key and a key kept by the bank. To prepare for events such as clients losing their own keys, the bank keeps spare keys at its branches in special envelopes closed with a seal.

Imamura managed to evade suspicion by employing various tactics such as pretending that there was a power outage when a customer unexpectedly showed up to check the deposit box.

“I was aware of the customer’s usage cycle and would decide which safe deposit boxes to steal from,” the suspect was quoted as saying during a voluntary questioning before her arrest.

To avoid detection, she would transfer the same amount of cash she had stolen from another customer's safe deposit box on the day the customer was scheduled to visit the branch, or store the stolen gold bars at a pawn shop.

If customers noticed the loss, she would tell them that she would investigate the matter and send them home. Then, she would return the missing amount to the safe deposit box and contact them later to inform them that it had been found.

Although an MUFG Bank unit had checked whether the keys were properly managed on a regular basis, it failed to conduct thorough checks, such as whether the envelope's seals had been broken.

MUFG Bank launched its probe into the thefts at the end of October last year, after a client reported that the contents of their safe deposit box were missing.

As Imamura admitted to the thefts, the bank dismissed her on Nov. 14.

Safe deposit boxes at other MUFG Bank branches were left unharmed. The bank also did not find the involvement of any individuals other than Imamura.

Safe deposit boxes are under fresh scrutiny following the incident, which has highlighted the inability of banks to verify the contents of customer’s boxes. While the contents are not disclosed primarily for privacy reasons, experts warn of the risks of tax evasion and criminal misuse.

Regulators do not explicitly prohibit such storing of cash, leaving loopholes for unmonitored financial activity.

Safe deposit boxes, available in automated (where opening and closing are electronically recorded), semi-automated (which logs entry and exit to the vault), and manual types (requiring an employee to accompany the customer and use a key), are often used by wealthy individuals to store valuables and cash. Automated boxes are the most secure type, but replacing existing setups is a pricey proposition for the banks, which don't make any direct profit from the deposit boxes.

In a news conference, MUFG Bank President Junichi Hanzawa acknowledged the risks of not being able to ascertain the contents of the safe deposit boxes but did not propose any specific changes.

“We will consider how we should adapt in light of customers’ needs,” he said.

Translated by The Japan Times