Kering SA appointed Balenciaga designer Demna Gvasalia to oversee a makeover of its struggling Gucci fashion label, disappointing investors who had expected a high-profile external hire.

Shares in Kering sank, after the French fashion conglomerate named the provocative designer Demna as artistic director of Gucci, its largest brand. Kering stock recently stood more than 13% lower, putting the shares on course for one of their biggest one-day drops on record,

Kering shares tanked on Friday morning after the group led by Francois-Henri Pinault chose to bet on subversive in-house talent Demna to reinvigorate its Gucci label rather than hiring a big-ticket name from fashion's overheating job market.