NatWest announced 15 months ago that it was winding down its Irish Ulster Bank unit and said on Wednesday that it had binding agreements in place for 90% of a total loan book that stood at about 20 billion euros.
AIB said the loans were worth 5.7 billion euros and would add 47,000 customers to the bank. The mortgages, which track the European Central Bank interest rate, a product no longer available on the market, will be administered by a third party service provider, AIB added.
Ireland's largest mortgage lender expects the deal to generate annual income of around 90 million euros, a 30 basis points average servicing cost and cut its common equity Tier 1 (CET1) by around 70 basis points.
AIB had a fully loaded CET1 ratio of 16.6% at the end of March, well above its medium term target of 13.5%.
Belgian financial group KBC swiftly followed NatWest in announcing its exit from the Irish market last year and the two departing banks' loan books have so far been carved up between Ireland's three remaining high street lenders.
AIB has also acquired 3.7 billion euros of Ulster Bank's commercial loans, while Permanent TSB paid 6.4 billion euros and gave NatWest a 16.66% share in the bank in exchange for Ulster's non-tracker mortgage and micro-SME lending books and its asset finance business.
Bank of Ireland, the country's largest bank by assets, agreed in October to a 5-billion euro deal to buy "substantially all" of KBC's Irish performing assets.
($1 = 0.9397 euros)
(Reporting by Padraic Halpin; Editing by Nick Zieminski)
