In the spring of 2025, criminals used phishing sites to take over customer accounts at several Japanese online brokerages and place unauthorised trades. Our online channel had 41,000 enabled accounts, protected by a password and a one-time code sent by email or SMS. We had suffered no takeover, but our customers received the same phishing messages, and a one-time code can be typed into a fake site as easily as a password.
In May I recommended that from October every online sign-in require a passkey on the customer's phone or a hardware security key, with no SMS fallback. Daichi Morosawa, who runs our online services, argued for keeping SMS codes for customers whose phones could not hold a passkey; he expected several thousand to leave the channel. I accepted that the channel would shrink. A fallback that phishing could defeat would simply have become the route attackers used, and the president agreed.
We spent ¥118 million on development, 6,000 hardware keys and extra contact-centre staff. Advisers helped customers enrol during home visits and at branches through the summer. Customers who could not or would not enrol were offered telephone ordering at online commission rates for twelve months, which we estimated would forgo about ¥46 million of commission.
By the October deadline, 33,800 customers had enrolled passkeys and 2,100 were using hardware keys. Of the remaining 5,100, 3,400 chose telephone ordering and 1,700 did not respond; their online access was suspended until they enrolled at a branch. Contact-centre calls rose 31 per cent for nine weeks. We have had no online account takeover since, though I cannot claim the change alone explains that. I would have tested enrolment with customers over seventy-five before announcing the date. I would also have presented hardware keys as an equal option from the start, rather than as a fallback that some customers felt marked them out as less capable.