The state-backed lender’s market share of new mortgage business stands at around 12%.
Targeted growth in mortgage lending helped net loans and advances increase by £0.4bn quarter-on-quarter, RBS said.
Customers at the bank, which includes NatWest, carried out 60% of mortgage switching online in the year to date, as overall digital sales increased 22% annually.
RBS profit before tax for the quarter came in at £961m, up from £871m compared to the same period last year.
However, overall bad loans shot up to £240m from £143m of impairment losses in 2017.
And the lender reported an additional £100m impairment charge, reflecting the more uncertain economic outlook.
Another £200m was also put aside for Payment Protection Insurance (PPI) complaints and compensation.
