SoftBank Group shares surged for a third day on Tuesday, following the explosive rally of its Arm Holdings, the chip designer that has almost doubled in value since making the case last week for how it will benefit from the artificial intelligence (AI) boom.

SoftBank’s stock climbed as much as 11% to the highest level since May 2021. SoftBank held onto a stake of about 90% in Arm as it took the company public last year.

Arm’s shares rose 29% on Monday, pushing its gains to more than 90% since it reported financial results on Feb. 7. The company is expanding beyond its traditional base in smartphone technology into new markets like artificial intelligence applications, lifting its outlook.