Late last week, Fitch Ratings concluded the review of the credit ratings assigned to the four major banks initiated at the end of last month. The long term issuer default ratings assigned to CBA, National Australia Bank and Westpac were lowered one notch to AA-. Fitch affirmed the AA- long term issuer default rating assigned to ANZ.In a commentary, Fitch wrote that the downgrades "reflect the weaker funding profile of the major Australian banks relative to similarly rated international peers. Despite some improvement since 2008, all four banks retain a reliance on wholesale funding, particularly from offshore markets."At the same time, Fitch lowered the ratings assigned to the hybrid and preferred securities issued by CBA, NAB and Westpac by three notches to BBB. The multiple-notch downgrade of the securities reflects "the application of Fitch's new bank regulatory capital securities rating criteria. "In Australia, payment of distributions on Tier 1 instruments is subject to an annual profits test. Fitch believes this is an easily activated non-performance trigger and therefore rates Australian banks preference shares five notches below an institution's viability rating," said the ratings agency.