SoftBank Group will acquire digital infrastructure investor DigitalBridge Group in a deal valued at $4 billion, the companies announced on Monday, as the Japanese investment firm seeks to expand its AI-focused portfolio.

The acquisition will increase SoftBank’s exposure to digital infrastructure, aligning with the conglomerate’s strategy to strengthen its position in artificial intelligence.

Following the announcement, DigitalBridge shares rose about 9.7% to $15.27 on Monday, after earlier surging 45% this month when Bloomberg News first reported the acquisition talks. The $16-per-share offer represents a 15% premium over DigitalBridge’s closing price on Friday, valuing the company at $2.92 billion. The deal is expected to close in the second half of next year.

SoftBank founder Masayoshi Son aims to capitalize on the growing demand for computing capacity that underpins AI applications.