NihonRates

Informational purposes only

NihonRates publishes commentary and analysis on the Japanese yen money market for general informational purposes. Nothing on this site constitutes investment, trading, tax, legal, or financial advice. You should consult qualified professionals before making financial decisions.

Site operator

NihonRates is operated by Arx Engineering. For questions about this site, contact us via www.arxeng.com/contact.

Non-affiliation

This website is an independent project. It is not affiliated with, endorsed by, sponsored by, or acting on behalf of the JBA TIBOR Administration, the Japanese Bankers Association, the Bank of Japan, any TIBOR reference bank, or any other official rate-setting body. NihonRates is not an authorized JBA TIBOR information provider.

Benchmark regulation and no contractual use

NihonRates is not a benchmark administrator, benchmark contributor, or benchmark user within the meaning of the EU Benchmark Regulation (BMR) or any equivalent national or international benchmark framework. We do not publish, administer, endorse, or submit to official benchmark registers.

We do not publish official fixing levels. The measurements that appear in our analysis - changes in basis points, spreads between tenors or between series, rolling volatility, distributional context, and historical “realized” comparisons - are derived statistics we compute ourselves from information published by the JBA TIBOR Administration and the Bank of Japan. They are strictly analytical and illustrative. They are not official JBA or Bank of Japan products, published benchmarks, forecasts of future fixings, or substitute reference rates, and they cannot be used to recover an official fixing.

Do not use any content from this website - including our exhibits, derived measurements, or any figure quoted in our commentary - as a reference rate, pricing input, or valuation basis in loan agreements, derivative contracts, swap agreements, structured products, regulatory filings, or any other binding financial or legal arrangement. For authoritative rates and permitted uses, rely only on the official sources listed below and their governing terms.

Data sources and accuracy

Our TIBOR analysis is computed from information posted by the JBA TIBOR Administration on its public website. Our TONA analysis is computed from Bank of Japan market data releases, with the Bank of Japan credited as source. Figures are read automatically from published files, so delays, transmission errors, parsing mistakes, or stale inputs may occur and would carry through into anything we publish. Always verify against the sources below before relying on our analysis for any purpose.

• JBA TIBOR Administration
• Bank of Japan TONA market data

Authoritative sources for TIBOR

The JBA TIBOR Administration posts JBA TIBOR on its own website for informational purposes only. JBATA states that JBA TIBOR is officially announced by the information providers it has authorized: Refinitiv Japan K.K., QUICK Corp., Jiji Press, Ltd., Bloomberg Finance L.P., and Nomura Research Institute, Ltd. NihonRates reads from JBATA's informational posting and is a further step removed again - we are not an authorized information provider, and nothing shown here is an official announcement. If you are using JBA TIBOR as a reference rate for concluding or executing a contract, or for any material decision, refer to one of the authorized providers listed above.

Basis of publication

NihonRates publishes its own analytical work about these publications, with the originating body credited. We claim no license from, authorization by, endorsement by, or affiliation with the JBA TIBOR Administration, the Japanese Bankers Association, or the Bank of Japan, and nothing on this site should be read as implying one. Those bodies publish their own terms of use and reserve their rights, including restrictions on reproduction for commercial purposes. Copying, redistribution, or resale of official rate data may require separate permission or licensing from them, which is one reason we do not reproduce it. Nothing on this site grants you any right in official data.

TONA provisional fixings

The Bank of Japan publishes a provisional TONA fixing (MP) on the same business day and a final fixing (MD) on the following business day. Our published analysis uses final fixings only. Where a provisional figure has necessarily informed a same-week observation, we say so in the issue.

How our published measurements are derived

Every figure in our analysis is something we computed. This section records how, so that a reader can judge the work rather than take it on trust. Each issue also states the period it covers and the calculation that produced each exhibit.

• Changes are differences between official fixings on two dates, expressed in basis points. A change does not disclose either level.
• Spreads are differences between tenors within a series, or between TIBOR and overnight TONA. Cross-series spreads are limited by the shorter TONA history we hold.
• Volatility is the rolling standard deviation of daily changes over a stated window, annualized where stated.
• Distributional context — percentile ranks, quintiles, ranked moves — is computed against the history we hold, whose start date is stated in the issue. It is not a statement about any period before then.
• Implied forwards use compound interest accrual on official spot rates with a 365-day year basis and conventional fixed tenor day mappings (for example, 3 months = 91 days, 6 months = 182 days). We publish forward errors and differences, not implied forward levels, because a level would invert back to the spots behind it.
• Realized comparisons use the arithmetic average of official daily fixings for the shorter tenor over the forward window — not the JBA trimmed-mean or any other official benchmark calculation method.
• Shape charts show the trajectory of a series without a value-calibrated axis. They are drawn to convey direction and relative magnitude, not readable levels.

These are analytical outputs, not official products, published benchmarks, or forecasts. Calculation errors, data gaps, and methodology limitations may affect them. Where a choice was arguable, we state which one we made.

No reliance

You use this website and its content at your own risk. We make no representation or warranty, express or implied, regarding the accuracy, completeness, timeliness, fitness for a particular purpose, or non-infringement of any content. All content is provided on an “as is” and “as available” basis.

To the fullest extent permitted by applicable law, Arx Engineering and the operators of NihonRates shall not be liable for any direct, indirect, incidental, consequential, special, or punitive damages, or for any loss of profits, revenue, data, or goodwill, arising from or related to your access to or use of - or reliance on - this website, its analysis, or its derived outputs, even if we have been advised of the possibility of such damages.

Trademarks

TIBOR, TONA, and related names and marks are the property of their respective owners. Use on this site is for descriptive and informational purposes only.

Rights holder contact

If you are a rights holder and consider that any content here exceeds permitted use, contact us at www.arxeng.com/contact. We will review promptly and remove or amend the content where appropriate.

Changes to this disclaimer

We may update this page from time to time. Material changes will be reflected in the last-updated date below.

Last updated: 2026-07-25