New analysis from interest.co.nz finds that New Zealand's biggest banks have been raising fixed mortgage rates in 2026 despite wholesale funding costs remaining flat. The gap between what banks pay to fund themselves and what they charge borrowers has narrowed — creating internal pressure on bank boards to restore margins.
New Zealand's major banks have been raising fixed mortgage rates across the board in 2026 — but the drivers behind those increases are more complex than a simple pass-through of wholesale costs.
Analysis from interest.co.nz shows that swap rates, a key input into the pricing of fixed mortgage rates, have not been rising in recent weeks. Yet the country's largest home loan lender, ANZ, has consistently moved rates higher — and its competitors have followed.
The gap between what banks pay to source funding in wholesale markets and what they charge borrowers on fixed mortgage rates — known as the margin — has been compressed. That compression has created internal pressure on bank boards to restore those margins, even without a corresponding rise in wholesale funding costs.
Markets are pricing an almost certain 25 basis point rise at the Reserve Bank's July 8 OCR review, and a further 25 basis point move by October. But the OCR itself, currently at 2.25 percent, only tangentially influences fixed mortgage rates — mainly at the short end. Fixed rates are predominantly set by swap rate markets, which move based on a wide range of local and international factors.
New Zealand is a debtor nation that funds a significant portion of its needs in offshore markets. That means wholesale rates are influenced by global conditions as well as domestic monetary policy. When offshore funding costs shift — whether due to global risk sentiment, US Federal Reserve policy, or geopolitical developments — New Zealand banks adjust their fixed rate pricing accordingly.
ANZ's decision to raise all fixed mortgage rates while only partially lifting term deposit rates was noted by analysts as a signal that margin restoration, rather than cost passthrough, was the primary motive. For borrowers, this means the rate they are offered on a fixed mortgage is not solely a reflection of what the bank pays to fund itself — it also reflects the commercial pressure on banks to maintain their profitability.
Fixed mortgage rates remain a commercial product, and the gap between a bank's funding costs and its lending rates can widen or narrow based on competitive dynamics and board-level profitability targets. Borrowers who are aware of this dynamic may find it useful to compare offers across multiple lenders, particularly at times when swap rates are stable but retail rates are moving.
The next OCR review is on July 8. A rise at that review would further influence shorter fixed term rates, but longer-term fixed rates are set further out on the swap curve and may already reflect current expectations.
This article is for general information only and is not personalised financial advice. Seek advice from a licensed financial adviser (registered on the FSPR) for guidance specific to your situation.