The supermarket giant entered the mortgage market in August 2012 and had balances of £700m at the end of 2013.
Sales in the three months to May 2014 across the Tesco Bank range were 3.6% up on the same period last year, its latest trading statement showed.
The wider Tesco group recorded falling sales for the latest three month reporting period. Like-for-like UK sales, including VAT but excluding petrol, fell by 3.7%.
Tesco said it has completed 4,000 mortgages since launch with an average loan size of £170,000. Across its book the lender said the average loan-to-value ratio was just over 50%.
It said across all areas of its banking business, including mortgages, credit cards, savings and other loans, 86% of product sales were online. Across all these sectors the number of customer accounts grew 14% to seven million.
Tesco Bank generated a £194m trading profit on revenues of £1bn in 2013.
