Citigroup downgraded Lululemon stock, but it still sees some upside.Lululemon Athletica (LULU 2.18%) has been one of the most disruptive companies in the apparel industry in the last generation. It essentially invented the athleisure segment, making high-end yoga pants fashionable, but it has struggled recently, and now, one prominent Wall Street analyst has cut his rating on the stock.Citi cools on LululemonIn a note on Thursday, Citigroup analyst Paul Lejuez downgraded Lululemon from buy to neutral and lo ...