Arm Holdings climbed 25% in its trading debut after raising $4.87 billion in the year’s biggest initial public offering, delivering a boost for both equity markets and SoftBank Group founder Masayoshi Son.

Shares in the chip designer, still 90% owned by SoftBank, closed at $63.59 in New York trading Thursday, giving Arm a market value of more than $65 billion. Including restricted share units, Arm’s fully diluted valuation is closer to $68 billion.

On Wednesday, Arm sold 95.5 million American depositary shares at the top of a marketed range of $47 to $51 each. The shares opened trading Thursday at $56.10 and rose as much as 30%.