Dutch lender ING Group’s retail banking unit has reported a total underlying income of EUR2.79bn for the fourth quarter of 2015, a 3.4% increase compared to EUR2.70bn for the same period of 2014.

This rise in underlying income was driven by the retail challengers and growth markets, particularly Germany.

The unit’s underlying result before tax was EUR902m, a surge of 58.5% compared to EUR569m a year ago.

During the period, operating expenses decreased 10.5% to EUR1.69bn from EUR1.88bn a year earlier.

This decline was mainly driven by EUR325m of redundancy provisions posted in the prior year, partly offset by EUR56m of higher regulatory costs as well as an addition to the provision for potential compensation regarding some floating interest rate loans and interest rate derivatives sold in the Netherlands.

Overall, the banking group registered a net result of EUR819m in the fourth quarter, a 30.4% decrease compared to EUR1.18bn in the corresponding quarter of 2014.

ING Group CEO Ralph Hamers said: "In 2015, our retail customer base grew by over 1.4 million new customers to 34.4 million at year-end; of this total, the number of customers selecting ING as their primary bank rose by almost 7% to 8.9 million.

"Net growth in our core lending book was EUR 21.7 billion, or 4.2%, as we continued to support our clients’ financing needs throughout the business cycle. Net customer deposits grew by EUR 25.1 billion, or 5.1%."