Arm stock jumps over 20% in highly anticipated IPO

British chipmaker Arm (ARM) debuted on the public markets on Thursday, opening at $56.10 in afternoon trading.

Arm’s shares jumped 10% right as trading began and climbed over 20% to above $61 in the first 30 minutes of trading. Going into the IPO, shares were priced at $51 each.

The company opened trading with a $54.5 billion valuation, but the company’s market cap already has jumped north of $60 billion.

The chipmaker’s go-public is the most high-profile IPO that the Nasdaq has seen since…