SYDNEY (S&P Global Ratings) Sept. 13, 2017--S&P Global Ratings today said it has assigned its 'BB+' issue credit rating to the Additional Tier 1 capital securities that Westpac Banking Corp. (Westpac; AA-/Negative/A-1+) has proposed to issue out of the bank's New Zealand branch. The securities are fixed-rate resetting perpetual subordinated contingent convertible securities. We rate these securities four notches below Westpac's stand-alone credit profile of 'a-'. 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. The following factors reflect the difference: The securities' subordinated status (deduct one notch); The risk of partial or untimely payment of coupons, in our view (deduct