The starting gun has been fired on one of the most eagerly anticipated stock market flotations of this – or, indeed, any - year. Arm Holdings, the UK-based chip designer, has filed for an Initial Public Offering (IPO) next month on the Nasdaq. It is expected to be the biggest IPO this year and the largest since Rivian, the electric vehicle maker, came to market in November 2021 with a valuation of $70bn. The filing contains plenty of information about how Cambridge-based Arm, which employs 2,800 people in the UK, has been trading of late. But the single most important...