Rakuten Group Inc. is emerging as the first real digital contender to Japan’s traditional lenders, using its Amazon.com like e-commerce dominance to steer users to its online bank.

New digital bank accounts with the internet conglomerate better known for its online shopping services expanded by 20% last year and recently topped 10 million, the most among the country’s online lenders.

Deposits grew by about 50% over the same period to more than ¥5 trillion, putting it on par with Japan’s mid-sized regional banks.