Retail finance provider Zip Co benefited from growing consumer demand for "buy now pay later" payment options, with an 80 per cent increase in customer numbers over the year to June and a 108 per cent increase in revenue.Zip's income increased from $39.3 million in 2017/18 to $82.9 million in the year to June. Customer numbers grew to 1.3 million and it processed 4.8 million transactions worth A$1.1 billionThe company has targeted an increase to 2.5 million customers during the current financial year.At June 30, the company's receivables were worth $682.6 million - an increase of 116 per cent.Net bad debt write-offs fell from 2.6 per cent to 1.6 per cent of receivables.The number of retail partners grew from 10,600 to 16,200.The company is still in its development phase, with an overseas acquisition announced earlier this month and new products in the pipeline. It reported a loss of $11.1 million, compared with a loss of $22.5 million in 2017/18.It entered into an agreement to acquire New Zealand buy now pay later company PartPay, which also has operations in the United Kingdom. The PartPay deal also gives it a 15 per cent stake in US company Quadpay.Yesterday it flagged the launch of a small business product. ZipBiz will provide an instalment payment facility for businesses purchases worth up to $25,000.The personal financial management app, Pocketbook, has 700,000 users.The company put itself on a sounder funding basis. At June 30, it had $631 million of funding available, of which $587 was utilised. The facility increased to $731 million last month following an increase provided by NAB in the zipMoney Trust 2017-1.NAB is currently arranging a further $400 million of funding through the implementation of the Zip Master Trust program.