Apple on Thursday estimated that tariffs will add about $900 million in costs to the quarter ending in June if rates do not change, with CEO Tim Cook outlining profound changes to the company’s supply chain to minimize the impact of President Trump’s trade war. Apple shares were down 3.8% after the company released quarterly results. While the results were better than analysts had expected, investors are focused on how tariff concerns will play out in the coming quarter. Apple executives said that the company expects low-to-mid single-digit revenue growth during its fiscal third quarter, which is in line with…