Here's one example of a person employed by Apple to work on OSM: https://www.openstreetmap.org/user/andrewwiseman

Facebook and Microsoft are also "Gold Corporate Members" of OSM which costs €10,000 / year, and they are "Corporate Partners" of the Humanitarian OpenStreetMap Team, which does employ people to directly work on OSM: https://www.hotosm.org/.

Also apparently "nearly 17% of the global road network was last edited by a corporate data-team member" (https://2020.stateofthemap.org/sessions/SPRQVZ/), and lots of people must be employed by corporations to make that happen, even if it's mostly automated edits.