With a market cap of $851 billion at the end of trading on Friday, Microsoft took back the crown, regaining a position it held eight years ago.

Microsoft is reaping the benefits of CEO Satya Nadella’s strategy to focus on its core profitable businesses, building out its existing strengths in enterprise and cloud computing via Azure, its platform that has accelerated in growth in the last three years. Azure is now second to Amazon Web Services in terms of market share.

At the same time, the tech giant accepted and cut its losses in the smartphone industry, ditching the Nokia mobile phone business that it had acquired under Steve Ballmer’s leadership in 2015. Nadella ended the business, letting go of 7,800 employees and a $7.6 billion charge three years ago and refocused Microsoft’s strategy around its best-selling services and products.

Apple also is facing challenges with the possibility of an American trade war with China that could lead to additional taxes and fees added to iPhones if President Trump’s threat to add a 10 percent tariff follows through.