SoftBank Group Corp. has raised $4.87 billion in the year's biggest initial public offering (IPO).

The IPO values Arm Holdings Plc at about $54.5 billion.

Arm is a chip designer whose technology is found in most of the world's smartphones.

The IPO was oversubscribed more than 10 times.

Arm's IPO could be a catalyst for IPOs from dozens of tech startups and other companies.

These companies have been stuck during the deepest, longest listing trough since the financial crisis in 2009.

Arm's IPO could also help to revive the tech IPO market in the US.

SoftBank CEO Masayoshi Son set the IPO price at $51 per share.

Son chose $51 per share, saying it wasn't worth risking a healthy debut for $100 million or so in additional proceeds.

Arm's IPO is the world's biggest this year.