AstraZeneca’s deal talks with US-headquartered Bristol Myers Squibb, which Semafor confirms remain active, would strike another blow to the UK’s effort to keep hold of its corporate champions. (A similar demand from US regulators has tripped up the sale of T-Mobile to Germany’s Deutsche Telekom, Semafor scooped last week.) Six former FTSE 100 companies have relisted in New York over the last five years, reflecting higher stock valuations and their increasingly global businesses. Those that remain in the UK are juicy takeover targets because they typically trade at much lower multiples than their US counterparts. Four FTSE 100 companies have been acquired by US rivals over that period; the latest, Segro, agreed to a $19 billion deal from US REIT Prologis today.