Shares of online-education company 2U Inc. /zigman2/quotes/201921395/composite TWOU -4.98% were plunging in Wednesday morning trading after Piper Sandler analyst Arvind Ramnani downgraded the stock to underweight from neutral, citing "multiple headwinds facing the industry and business model." Ramnani is concerned about regulatory risk as it relates to the company's revenue-share agreements, the possibility of "digital-learning fatigue," and the potential for the company's university partners to insource management of online programs. "We understand the complexity of bringing these programs in-house and 2U has retained all of its large clients; however, in our view, some of these large programs could potentially re-negotiate economics," he wrote in his note to clients. Ramnani further noted that while the company's EdX acquisition could help it lower its customer-acquisition costs and potentially make 2U emerge as a more attractive takeover candidate itself, he sees "material" regulatory risks for the company. Shares have declined 75% over the past 12 months as the S&P 500 [s:SPX] has lost 17%.