ING Australia is set to announce a statutory net profit after tax of A$348 million for 2017, equating to an 18 per cent rise on the previous year's results.The earnings came with record customer growth of more than 300,000 new customers. There was also a jump in the number of customers treating ING as their main bank, meaning existing customers shifted more business to ING. The bank said 40 per cent of this year's new customer growth came from the referrals of existing customers.ING Australia's chief executive officer Uday Sareen said more than 410,000 Australians use ING as their main bank - a 68 per cent rise. There are now more than 850,000 Orange Everyday accounts, with just shy of 400,000 opened in the last year.Total customers' savings are up 8.3 per cent to $39.8 million, largely funding the increase in total loans of $52.5 million, a rise of 9.9 per cent on the previous year.ING, which began life as an online savings bank, has been moving into business banking, a strategy Sareen said was helping to diversify the bank's income and loans.This year, wholesale bank and business lending accounted for close to a third of all new loan growth over the year."ING has global reach and expertise in wholesale lending and we plan to continue growing and serving more corporate customers in Australia in 2018 with a focus on real estate, utilities and infrastructure, metals and mining, oil and gas, telecommunications and media," Sareen said.This expansion will be a whole lot easier, as ING Australia achieved advanced bank accreditation earlier this month - that is, it can use internal risk models to calculate its regulatory capital requirements across all lending activities.