Activists have called out Oatly's decision to partner with Blackstone, which partially owns two firms linked to Amazon deforestation. : Vegan milk brand Oatly is facing activist pressure after private equity firm Blackstone, headed by Trump-supporting billionaire Stephen Schwarzman, acquired a stake in the company. The Swedish oat-milk maker sold a $200 million stake in July to a consortium including Blackstone, Oprah Winfrey, Natalie Portman, former Starbucks CEO Howard Schultz, and Jay-Z's entertainment company Roc Nation.