SBI Securities and Yahoo Japan have announced support for a joint login service. From SBI Group Official press release:

SBI SECURITIES Co., Ltd. (Headquarters: Minato-ku, Tokyo; President: Masato Takamura; hereinafter “SBI SECURITIES”) will be operating SBI Holdings, Inc. (Headquarters: Minato-ku, Tokyo Alliance measures in the securities business based on the business alliance in the financial services business announced by CEO: Yoshitaka Kitao) and Z Holdings Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo; CEO: Kentaro Kawabe, hereinafter “Z Holdings”) As a first step, we are pleased to announce that we will start logging in to SBI SECURITIES ‘website using “Yahoo! JAPAN ID” from March 30, 2020 (Monday).

Starting Monday, March 30th, 2020, SBI Securities website will now allow users to log in using a Yahoo Japan ID and password. According to Kentaro Kawabe is Senior Executive Vice President Corporate Officer & Chief Operating Officer at Yahoo! JAPAN:

It will be possible to simplify login and realize quick securities trading (a separate trading password is required when trading with SBI Securities). “Forgot username / login password” is always ranked high in the number of inquiries to SBI SECURITIES ‘customer service center.

Later this year, the two companies will make it possible to open an account with SBI from Yahoo Finance, making it possible to browse stocks held by SBI.

This was first pointed out by: