Sumitomo Mitsui DS Asset Management: it detected unauthorized access at the contractor behind its direct-sales fund site and took My Page offline for about 10 hours

Sumitomo Mitsui DS Asset Management took My Page of its fund direct-sales site offline for about 10 hours after unauthorized access at a contractor; no account impact was found.

Disclosed

2026-10-16

Organizations involved

Leaked or at risk

Unknown

Downtime

Unknown

What happened

2026-10-15
At about 19:50 it detected unauthorized access at the trading contractor's system and stopped it as a precaution; My Page logins stopped working. [1]
2026-10-16
Service was restored at about 06:00 and the company announced what happened the same day. No impact on account information or trades was found. [1] [2]

–

[Breached][Moderate]Tokyo, MinatoFinance and insurance
Sumitomo Mitsui DS Asset Management Company, Limited
The system of the trading contractor behind its fund direct-sales service was accessed without authorization, and it shut My Page as a precaution.

						Note
Sumitomo Mitsui DS Asset Management Company, Limited	[Breached]	[Moderate]	Tokyo, Minato	Finance and insurance	Unknown	The system of the trading contractor behind its fund direct-sales service was accessed without authorization, and it shut My Page as a precaution.