Thirty mortgage providers have not passed on the base rate increase to customers on their standard variable rate (SVR).
The Bank of England increased base rate by 0.25% to 0.5% in early November, leading many banks and building societies to increase their SVRs.
Major players such as Barclays, Halifax, Lloyds Bank, and Santander passed on the full 0.25% base rate rise to borrowers on 1 December 2017.
However, research published by comparison service Moneyfacts shows that the average SVR increased from 4.6% in November to 4.74% in December as many smaller providers chose to keep their rates the same.
Many mutuals, such as Newcastle Building Society and Skipton Building Society, have kept their SVRs at their previous levels.
In total, there are 30 providers (44% of providers) which have not passed any base rate increase on to borrowers.
Regardless, Moneyfacts says it expects the base rate rise to spark an increase in remortgaging, with many consumers moving from expensive SVR deals to cheaper fixed term products.
A homeowner borrowing £150,000 over 25 years could save £192.66 a month by switching from the average SVR to today’s average two-year fixed rate at 2.35%.
Charlotte Nelson, finance expert at Moneyfacts, says: “Many would have predicted that a 0.25% rise in the base rate would translate to a similar increase to the average SVR.
“In fact, just 56% of providers have passed on a rise to their SVR, with seven of them choosing to increase their rates by less than the 0.25%, which has caused the average SVR to rise more modestly.
“Historically, a base rate rise would mean that all variable rates would increase too – and it would be more of a question of when, not if, they would do so. However, this time, providers who are keen to be seen on the side of the borrower may have opted to either not increase by the full amount, or not pass on the rate rise at all.”