Shares of Arm opened Thursday at $56.10 on the Nasdaq, up $5.10 from its IPO price of $51. The stock closed at $63.59, a gain of $12.59. At $63.59 a share, Arm is valued at $65.2 billion. 

Jason Child, Arm’s CFO, told Fortune he wasn’t worried about the IPO. Arm met with 45 different investors during the roadshow, which began after Labor Day. The Arm IPO ended up being oversubscribed by a healthy margin, Child said. This helped Arm price at $51, the top end of its $47–$51 price range, he said.

“I’ve only done one other IPO before, but generally those are the signals that tell you things should be in pretty good shape,” said Child, who is the former CFO of Groupon and helped lead its public offering. 

On Wednesday, Arm ended up delivering the year’s biggest IPO when it raised $4.87 billion. Twenty-seven banks are listed as working on the Arm IPO. Barclays, Goldman Sachs, J.P. Morgan, and Mizuho are the lead banks on the offering. Goldman is also lead book runner on the Instacart and Klaviyo IPOs, which are scheduled to trade next week. 

“I am very happy with the IPO execution and happy for all the Arm employees. Every employee is now an owner,” Child said. 

Arm designs the CPUs, or chips, that power more than 99% of the world’s smartphones, according to its regulatory filing. Arm won’t get any money from the IPO; all the shares are coming from its parent, SoftBank, which will own 90% after the deal.

This isn’t Arm’s first IPO. The U.K. company first went public in 1998 when it was traded on the London Stock Exchange and the Nasdaq. SoftBank acquired Arm in 2016 in a deal then valued at $32 billion. In 2020, Nvidia agreed to buy Arm in a $40 billion transaction, but regulatory issues caused the parties to call off the deal in February 2022. Arm, at this time, said it would start preparing for an IPO. It hired Child to be its CFO the following September.  

Arm’s solid debut is “a very positive signal for the fall IPO market that [Arm] is trading up,” said Matt Kennedy, senior IPO strategist at Renaissance Capital, a provider of pre-IPO research that manages two IPO-focused ETFs (NYSE: IPO, IPOS). Arm is the first major tech IPO of 2023 and the biggest new issue since EV maker Rivian collected nearly $12 billion in November 2021, Kennedy noted.

Right now, Arm’s stock is performing well. But many IPOs typically trade up their first day and then lose those gains in the following weeks. Consider Rivian, which delivered a great debut in November 2021 when its stock rose 29% from its $78 offer price. Rivian’s stock managed to stay above $78 for several weeks before it dropped below its IPO price in January 2022. Rivian shares this year have remained below $78, hitting a low of $11.68 in April. On Thursday, Rivian stock rose nearly 3% to $23.95 in afternoon trading. The Renaissance Capital ETF, which contains the largest and most liquid IPOs since mid-2020, is up 34% as of Sept. 14.

“From here, [Arm] needs to prove that it can follow through on its plan. The first day of the IPO is just one day and [Arm] has ambitious plans to expand margins and benefit from AI to trade above $60 where it is now,” Kennedy said.