Haleon shares are scheduled to open for trading on Monday July 18 after investors in GSK – formerly GlaxoSmithKline – voted in favor of the split. The FTSE 100 company won 99.8% of the vote at a general meeting on Wednesday at a hotel at London’s Heathrow Airport. Haleon, whose portfolio of brands will include Sensodyne toothpaste and painkillers Advil and Panadol, is expected to seek a valuation of up to £45bn. The approval paves the way for a listing that will be used to gauge the financial health of the City of London after Brexit, with the formation of a company sure to join its current owner on the FTSE 100 index of blue-chip shares. The last IPO on a similar scale was the entry of mining and commodities company Glencore with a market value of £38bn in 2011. London looks set to lose out to New York on the planned return to public markets of Arm, the Cambridge chip designer owned by Japan’s Softbank. The UK government has lobbied hard for Arm to have a secondary listing in London amid concerns it could lose another major UK-based distributor. The London Stock Exchange has been described as being in “secular decline”, with the number of listed companies falling from more than 4,400 in the early 1960s to fewer than 1,200 today. Supermarket Morrisons went public last year, the biggest in a wave of private equity takeovers triggered when share prices fell during the pandemic. Haleon will employ 23,000 employees in 100 countries. Its business had revenues of £9.5bn and profits of £1.6bn in 2021, according to its share offering prospectus. Haleon – whose name refers to ‘hale’, synonymous with healthy, and ‘leon’, which contains the Latin for ‘lion’ – has nine multinational brands, including pain relief supplements Voltaren and Centrum, which account for nearly 60% of revenue. . Sir Dave Lewis, the former chief executive of Tesco, has been appointed as non-executive chairman of the company. Brian McNamara, a former Procter & Gamble and Novartis executive, will continue to lead the company, having led it as a division of GSK since 2016. Bankers, lawyers and advisers will collect up to £117m in transaction costs related to the demerger, according to the prospectus. GSK board members, including chief executive Emma Walmsley, faced a mixed reception at the meeting. A single shareholder called for a round of applause for going through with the split, but others questioned the logic of the deal and whether it was a mistake to reject a £50bn bid late last year from Unilever, another FTSE 100 consumer goods company. Analysts at Credit Suisse have since given Haleon an equity valuation of £33bn, while other analysts have valued it at up to £40bn, plus a debt pile worth more than £10bn after paying £7bn worth of dividends to GSK and £3bn pounds to Pfizer. GSK had argued that Unilever’s bid undervalued the company – although that was before the prospect of rising interest rates hit global stock indexes and the energy price shock threatened to trigger a worldwide recession. “I think it’s really bad for shareholders to suffer such a consequence,” said one shareholder. Subscribe to the Business Today daily email or follow Guardian Business on Twitter @BusinessDesk But Sir Jonathan Symonds, chairman of GSK, said Haleon had a “very competitive growth profile” and its sales would prove resilient against rising inflation in many economies around the world. Haleon’s over-the-counter products will provide a “very quick and good way for consumers to access medicine,” he said. “We’re here ready with two very attractive companies with an opportunity to grow,” Symonds said, referring to GSK and Haleon. After the demerger is completed, GSK shareholders will own 54.5% of Haleon, while GSK will still own approximately 6% and control an additional 7.5%. GSK’s pharmaceutical rival Pfizer will initially own almost a third of the company, which was set up in 2019 as a joint venture, although the US company holds a minority stake. Pfizer said it would gradually sell its stake after the listing.