Arm Holdings Plc

An IPO case study



  • We advised Arm Holdings plc (“Arm”) on the UK aspects of its initial public offering on the Nasdaq Global Select Market (“Nasdaq”).
  • Arm’s market capitalisation was USD 52.3 billion upon the listing of the 95,500,000 American depository shares on 14 September 2023.
  • UK-headquartered Arm is one of our long-standing clients and we were delighted to support their next phase of transformative growth.

Background to Arm

Background to Arm

Headquartered in the UK, Arm architects, develops, and licenses high-performance, low-cost, and energy-efficient CPU products and related technology, on which many of the world’s leading semiconductor companies and OEMs rely to develop their products.

Arm’s energy-efficient CPUs have enabled advanced computing in more than 99% of the world’s smartphones, for the year ended 31 December 2022, and more than 250 billion chips, cumulatively, powering everything from the tiniest of sensors to the most powerful supercomputers.

Arm was established in 1990 and was listed on the London Stock Exchange from 1998 until 2016, when it was taken private by SoftBank Group.

How did we add value?


  • We advised and assisted Arm with its preliminary IPO structuring considerations, including as to the most appropriate listing venue.
  • We advised Arm on a pre-IPO reorganisation which involved the exchange of shares in Arm Limited for shares in Arm Holdings, the release and re-application of security on those shares, as well as a bonus issue and reduction of capital to create distributable reserves for Arm in excess of US$50 billion in connection with the reorganisation.
  • We advised Arm on the issue of American depositary shares and the structure of its shareholding which involved SoftBank Group holding its retained position through a structural safekeeping account in a bespoke arrangement with Citibank.
  • We also advised Arm on its tax structuring, including in relation to stamp duty and stamp duty reserve tax, in connection with the reorganisation and IPO.

Long standing relationship


This transaction represented a key milestone in Arm’s journey, on which Slaughter and May has been advising for a number of years. We have advised Arm on several important matters over the years, including:

  • Establishment of a joint venture for Arm’s semiconductor technology in China in July 2018; and
  • Takeover of Arm by Softbank Group in July 2016 for USD 32 billion.

Our deep understanding of Arm’s business allowed us to provide significant additional value on this transaction.

Key contacts