The Cambridge-based chip designer Arm is to pursue a US-only listing this year, dealing a major blow to Rishi Sunak’s ambitions to make London the first choice for tech company flotations. The company, which is owned by the Japanese conglomerate SoftBank, confirmed its preferred plan of seeking a US-only main listing later this year, spurning the UK despite heavy lobbying by successive prime ministers. Sunak, his predecessor Boris Johnson and an army of government and London Stock Exchange officials had held intermittent talks with SoftBank in an attempt to convince it of the merits of a dual, if not full, listing in London. Arm has previously had a dual listing on both sides of the Atlantic, before it was acquired by the Japanese company for £24.6bn in 2016, and had been a member of the FTSE for 18 years. Winning it back, after SoftBank decided on a flotation after the blocking of a $40bn takeover by the US firm Nvidia over competition concerns last year, would have been a huge boost for the capital’s longer-term ambitions to have more tech flotations. Arm did offer a consolation of indicating it would look at a subsequent London listing “in due course”. Rene Haas, the chief executive of Arm, said on Friday: “After engagement with the British government and the Financial Conduct Authority over several months, SoftBank and Arm have determined that pursuing a US-only listing of Arm in 2023 is the best path forward for the company and its stakeholders.” Arm, which is the world’s biggest supplier of chip design elements used in products from smartphones to games consoles, pledged to keep its headquarters, operations and “material intellectual property” in the UK. The company also said it intends to expand its presence with a new site in Bristol and “continued headcount”. “Arm is proud of its British heritage, and continues to work with the British government,” the company said. “We will continue to invest and play a significant role in the British tech ecosystem.” City analysts said Arm’s decision to choose the US was another blow to London’s attempt to build the tech credentials of the FTSE 100 after the disastrous flotation of Deliveroo and the almost 90% slump in the market value of the online retailer THG. “The UK blue chip index has struggled to attract key behemoths in the sector,” said Victoria Scholar, the head of investment at Interactive Investor. “There have also been some high-profile disasters in UK tech. Arm’s abandonment of London is another kick in the teeth for the Square Mile’s attractiveness among international investors as a go-to destination for technology giants.” The government and regulators have made changes to the UK’s listing rules in an effort to persuade fast-growing tech companies that London is a worthwhile place to list their shares. “The UK is taking forward ambitious reforms to the rules governing its capital markets,” a government spokesperson said. “We continue to attract some of the most innovative and largest companies in the world – and note Arm’s commitment to expanding its presence in the UK, providing a boost to growth, jobs and investment.”