S&P Global Ratings has assigned a BB+ issue credit rating to the A$1.25 billion Additional Tier 1 capital securities that Westpac (rated AA-/Negative) has proposed to issue out of its New Zealand branch. The securities are fixed-rate resetting perpetual subordinated contingent convertible securities. "We exclude a three-notch uplift for government support, reflecting our view that support from the Australian government is unlikely to extend to hybrid capital instruments issued by Westpac," S&P said in a media release yesterday. "We have assessed the proposed issue as having intermediate equity content. In our view, these securities would be able to absorb losses on a going-concern basis through non-payment of coupons, conversion into common equity, or principal write-down." As a small point of difference, Fitch Ratings has assigned the Westpac resetting perpetual subordinated contingent convertible securities a rating of BBB. The notes qualify as additional Tier 1 securities for regulatory capital purposes.Fitch noted: "Westpac can redeem all the notes on each reset date subject to the approval of APRA. The first reset date will be 21 September 2027 and additional reset dates will be every five years thereafter."On issuance these securities are expected to qualify as fully compliant Basel III Additional Tier 1 capital under APRA's rules. The securities are perpetual instruments with no fixed maturity date.Westpac reported a Level 1 CET1 ratio of 9.9 per cent and a Level 2 ratio of 10.0 per cent as at end-June 2017, 190 basis points and 200 bps, respectively, above the bank's Pillar 1 minimum of 8.0 per cent. Tier 1 and total capital buffers at Level 1 and 2 were higher. Fitch said it expected the bank to maintain a management buffer of about 100 bps over the regulatory minimum, even after the Australian regulator finalises its revisions to the capital adequacy framework.