Farfetch Ltd. stock took a beating in Friday trading after the online luxury retailer’s earnings report presented investors with a far different company from the one that went public a year ago. Farfetch FTCH, -1.81%   shares closed Friday down 44.5% in Friday trading, en route to the biggest one-day percentage decline since the company began trading in September 2018. The stock has tumbled 37.1% over the year to date while the Amplify Online Retail ETF IBUY, -0.72%   has gained 23.3% and the S&P 500 index SPX, -0.02%   has rallied 15.2%. Farfetch reported wider-than-expected second-quarter losses and announced the $675 million acquisition of New Guards Group, a platform that has launched a number of luxury brands, including Off White and Palm Angels. Off White is already one of the top 10 most popular brands on Farfetch, according to the announcement. The acquisition allows the company to add a “brand platform” to its existing platforms: “technology, data and logistics,” said José Manuel Ferreira Neves, Farfetch’s chief executive, on the earnings call, according to FactSet. Neves said Farfetch plans to relaunch the Off White website on its site in the fourth quarter, includ...