Japan Post Bank

Is Japan Post Bank safe?

For yen savings, yes, and for most savers it is among the lower-risk banks in Japan. Japan Post Bank held ¥186.3 trillion of deposits at 30 June 2026, mostly from households whose balances are held down by legal caps. It reported a capital ratio of 15.15% under Japan's domestic standard, against a 4% minimum, and Moody's and S&P rate it A1 and A, the same as Mizuho. Deposits are insured by the Deposit InsuranceDeposit insuranceA government-backed scheme that repays bank customers up to a set limit if their bank fails, such as the FDIC in the US or the FSCS in the UK.More in the glossary Corporation of Japan (DICJ) up to ¥10 million per depositor, and interest-free transfer deposits in full.

We score it 75/100, between Mizuho (73) and SMBC (76). The bank's balance sheet is not the concern. Its record of selling investment products to elderly customers, the misuse of savers' data at post offices, and fraud and outages on its payment services are.

What deposit insurance covers at Japan Post Bank

Japan Post Bank is a member of the DICJ like any other Japanese bank. The rules are the same as at MUFG or Mizuho:

Unlike the megabanks, it takes no foreign currency deposits, so a saver cannot end up holding an uninsured dollar account there by mistake.

Two features are particular to Japan Post Bank. First, the law caps deposits per person: ¥13 million for ordinary deposits and ¥13 million for time deposits, a total of ¥26 million since April 2019. Money that pushes an ordinary account past its cap is moved into an interest-free transfer deposit, which is insured in full. Second, postal savings made before 1 October 2007 are not Japan Post Bank deposits at all. A government agency manages them, and they are treated as lost 20 years and two months after maturity unless they are claimed.

Capital and liquidity

Japan Post Bank reports under Japan's domestic standard rather than the international rules the megabanks follow, so its headline ratio is not directly comparable. Its own estimate of an international-style CET1 ratio is lower, and on the fully loaded basis it sits just below its target range. That is the main reason capital scores below MUFG and Mizuho despite similar ratings.

Liquidity is the strongest part of the bank. It lends out only about 3% of its deposits. The rest sits in cash, deposits at other banks and securities, including ¥42.4 trillion of Japanese government bonds. Deposit caps keep individual balances small, and small household balances rarely run. The real exposure is to interest rates and markets: a large book of bonds and funds can lose value when rates rise, which affects capital, not the safety of insured deposits.

Conduct: elderly customers and savers' data

In September 2019 the bank disclosed that in 17,700 cases, 43% of the face-to-face sales it reviewed to customers aged 70 or over, staff had not obtained the manager approval its own rules required before offering an investment trust. The lapses were found at 213 branches, 91% of those selling the funds.

In September 2024 the Japan Post group admitted that post offices had used savers' non-public financial data, such as account balances, to target insurance sales without the customers' consent, which breaks the law. On 18 March 2025 the Financial Services Agency (FSA) ordered Japan Post Holdings, Japan Post, Japan Post Bank and Japan Post Insurance to report on the problem and their fixes. The group sent its reports in April 2025. We found no fines or business improvement orders against Japan Post Bank itself.

Fraud and outages

The worst digital failure came in 2020. Fraudsters linked victims' Japan Post Bank accounts to payment apps through its instant transfer service, and sent money between accounts of its mijica card. The bank wrote to about 5.5 million customers who had linked payment services, and by October 2020 had compensated 210 instant-transfer cases totalling ¥49.4 million and 54 mijica cases.

Outages have been shorter. On 23 April 2024 a system fault delayed incoming transfers from other banks from 8:40 a.m. until later in the day. On 22 September 2024 a fault in ATM partner services, debit cards and transfers left some balances reduced for transactions that did not go through; the bank refunded them within four days. On 7 April 2025 its online banking and passbook app were down for about three hours.

How to keep your money safe at Japan Post Bank

1. Keep interest-bearing deposits within ¥10 million if you want them all insured. For larger sums, use the interest-free transfer account, which is covered in full.
2. Treat investment trusts and insurance sold at the post office as investments, not savings. Ask for the product documents and take time to decide.
3. Look for old postal savings certificates from before October 2007 and claim them before they lapse.
4. Register for the bank's authentication app, check which payment apps are linked to your account, and remove any you do not use.

How we scored it

Liquidity (86) and stability (84) are Japan Post Bank's strongest factors: a deposit base of small household savings, little lending and no public capital since 2007. Digital security (58) is the weakest, for the 2020 fraud cases and repeated outages, followed by conduct (62). Capital (76) is solid but held back by a CET1CET1 ratioA bank's highest-quality capital (mainly shares and retained profits) as a share of its risk-weighted assets. Higher means more room to absorb losses.More in the glossary estimate near the bottom of its own target range.