Leerink analyst David Larsen views the Q1 results reported by Walgreens Boots Alliance as solid. The analyst is "especially pleased" with the company's gross margin in Retail USA given his concerns about reimbursement pressure and drug price inflation. Management's indication that they still view vertical integration as a positive implies that Walgreens at some point would likely be interested in purchasing all of AmerisourceBergen (ABC) and perhaps Express Scripts (ESRX), Larsen tells investors in a post-earnings research note. He adds that while a commercial agreement is also possible, an outright sale of Express Scripts to Walgreens is likely to create the most shareholder value. Another deal for Walgreens is likely a year or two away as the company integrates Rite Aid (RAD), Larsen points out. He keeps an Outperform rating on Walgreens. Jefferies analysts on December 15, 2015 discussed the potential of Walgreens buying Express Scripts in 2018.