OREANDA-NEWS. Fitch Ratings (Thailand) has today affirmed Japan-based Mizuho Bank, Ltd.'s (MHBK) THB3bn senior unsecured notes due September 2018 at 'AAA(tha)'. This follows the recent affirmation of MHBK's Long-Term Foreign-Currency Issuer Default Rating (IDR) at 'A-' with Stable Outlook on 17 November 2015 (see "Fitch Upgrades SMFG; Affirms Other Major Japanese Banks" at www.fitchratings.com).

KEY RATING DRIVERS

The National rating on the notes is based on MHBK's Long-Term Foreign-Currency Issuer Default Rating (IDR) of 'A-', which is at the same level with Thailand's Long-Term Local-Currency IDR of 'A-' and hence correlated to 'AAA(tha)', the highest rating on Thailand's National rating scale.

MHBK's Long-Term Foreign-Currency IDR is based on sovereign support, and is at the bank's Support Rating Floor (SRF) of 'A-' as the bank is considered a systemically important financial institution in Japan.

MHBK is one of the subsidiaries of Mizuho Financial Group, Inc. (A-/Stable). The group is the second-largest bank in Japan by total assets.

RATING SENSITIVITIES

The 'AAA(tha)' rating on MHBK's senior notes is the highest on the National scale and, hence, no rating upside is possible.

A downgrade could be triggered if MHBK's Long-Term Foreign-Currency IDR is lower than Thailand's Long-Term Local-Currency IDR, either through a downgrade of MHBK's rating or an upgrade of Thailand's rating. However, this is unlikely to occur in the near-term as reflected by their Stable Outlooks.

MHBK's other ratings are not affected and are as follows:
- Long-Term Foreign and Local Currency IDRs at 'A-'; Outlook Stable
- Short-Term Foreign and Local Currency IDRs at 'F1'
- Viability Rating at 'bbb+'
- Support Rating at '1'
- Support Rating Floor at 'A-'
- Senior unsecured debt at 'A-'