Sumitomo Mitsui Financial Group is preparing to take a stake in SBI Holdings, according to a person familiar with the matter, marking a major alliance between two Japanese financial giants.

Japan’s second-largest banking group plans to hold as much as 10% of SBI, a stake valued at about ¥60 billion ($443 million), the person said, asking not to be identified because the discussions are private.

The Tokyo-based companies will collaborate on the securities business, the Nikkei reported earlier Tuesday, citing a person it didn’t identify.

Representatives for SBI and Sumitomo Mitsui said nothing has been decided.

The deal would mark another significant acquisition for Sumitomo Mitsui after a string of deals. Speaking in an interview late last year, Chief Executive Officer Jun Ohta said he would weigh more transactions in the future after spending more than $3.3 billion in Asia in 2021.

SBI, Japan’s biggest online brokerage, has been expanding its banking operations by purchasing stakes in regional banks. It took control of mid-sized Japanese commercial lender Shinsei Bank last year, and is pursuing efforts to strengthen investment banking such as merger advising and securities underwriting.

In 2020, the two companies agreed to cooperate in a strategic and capital alliance where their units would cooperate in digital and other fields. They also planned to work together in smartphone-based securities, over-the-counter securities, and to set up a fund to invest in fintech ventures, the firms said at the time.