How Birkenstocks went from frumpy Dad sandal to fashion favourite: German orthopaedic shoe maker - set for $9.2bn New York listing - benefitted from Barbie boost and women ditching heels in lockdown
They've become the toast of the fashion world in recent years - and now Birkenstock is set to be valued at more than $9.2 billion in its eagerly awaited listing in New York.