SoftBank teams up with Sierra, AI customer service boosts resolution rate to 97%

Japan's SoftBank has partnered with US AI startup Sierra, making it the exclusive partner for Sierra in Japan. Sierra's conversational AI customer service system is now used by SoftBank's online-only brand LINEMO to handle customer inquiries.

After deploying the system, LINEMO's customer issue resolution rate jumped from 83% to 97%, and customer satisfaction rose from 74% to 93%. LINEMO has no physical stores and mainly provides support through online chat and the LINE app.

Sierra, founded by Bret Taylor and Clay Bavor, raised $950 million in 2026, valuing it at around $15.8 billion. The company says over 40% of Fortune 50 companies now use its AI software.

This deal is part of SoftBank's "Activate AI for Society" strategy. SoftBank is developing AI-powered call center solutions and plans to offer them to more businesses in Japan. However, SoftBank noted that large-scale rollout must comply with Japan's Personal Information Protection Law and cross-border data transfer rules.