SoftBank Corp. said on July 14 that it became Sierra’s exclusive partner in Japan after deploying the startup’s customer service AI at its online-only mobile brand, LINEMO.

The deployment increased inquiry resolution from 83% to 97%and customer satisfaction scores from 74% to 93%.

LINEMO is a fully online SoftBank mobile brand, with support handled through chat and LINE rather than physical stores.

Sierra, a US-based conversational AI startup founded by Bret Taylor and Clay Bavor, raised US$950 million at a US$15.8 billion post-money valuation in 2026.

It said more than 40% of Fortune 50 companies used its software.

The partnership is part of SoftBank Corp.’s “Activate AI for Society” strategy, which includes an AI-powered call center initiative that the company is developing for wider sale in Japan.

Further rollout will need to comply with Japan’s Act on the Protection of Personal Information (APPI) and other rules governing personal data and cross-border transfers.

SoftBank separately said those requirements are particularly strict for telecommunications customer communications.

🔗 Source: SoftBank Corp.

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