Retail veterans Solomon Lew and Mark McInnes have put to bed doubts about Premier Investments' strategic shift for its valuable Smiggle brand, flagging a surge in sales this year as Smiggle lunchboxes and pencil cases start selling in 180 more stores overseas.

Premier shares posted their strongest gains for more than 12 years, rising as much as 23 per cent to a 12-month high of $19.30 on Friday, after Mr Lew and Mr McInnes said Smiggle's "capital-light" global expansion plan, unveiled last September, was beating their expectations and was likely to be more profitable than the previous strategy of opening hundreds of standalone stores.