Popular mid-sized companies would normally hope to attract about 50 investors to an event to market an upcoming listing. But when Cellnex – a phone-tower operator owned by Spanish infrastructure firm Abertis – planned its float late last year, 110 investors piled into London’s Stationers’ Hall to hear about it.

José Aljaro Navarro, Abertis's chief financial officer, recalls: "It was like being at a wedding. Our target was US players - the American funds. We gave advantages to American and long-only investors and we had support of the American banks [Goldman Sachs and Morgan Stanley were global co-ordinators]."