https://arstechnica.com/gadgets/2019/04/lenovo-hp-continue-to-vie-for-top-spot-as-pc-market-falls-to-58-5-million-systems/

Gartner and IDC have both published their quarterly reports on the size of the PC market in the first quarter of 2019, and they've both agreed: about 58.5 million systems were shipped. The two companies use somewhat different definitions of PCs—for Gartner they're desktops, laptops, and "ultramobile premiums" such as the Surface Pro, but exclude Chromebooks and iPads; for IDC they're desktops, laptops, and workstations, including Chromebooks, but don't include any tablets at all—but this quarter they've ended up at almost exactly the same number of units sold.

The two analysts don't, however, agree on who the top seller was. IDC puts HP top, at 13.6 million systems (0.8 percent fewer than the same quarter a year ago) and a 23.2 percent market share, with Lenovo in second place, at 13.4 million systems (up 1.8 percent) and a 23.0 percent share of the market. Gartner, in contrast, puts Lenovo top at 13.2 million systems (up 6.9 percent), and a 22.5 percent share, and HP in second, with 12.8 million systems (up 0.8 percent) and a 21.9 percent share.