Data is very likely to be from LinkedIn if you look at the field descriptions and stats. The only field that is 100% available is the one based on the LinkedIn URL. I would guess scraping unless LinkedIn provides an API for this data that I can't find.
Most likely from scraping (crunchbase, yahoo,etc), unless they bought it from somewhere. In most countries you can get it from the chamber of commerce. Dun and Bradstreet and other similar companies. Some of these data aggregators will have partnership with other companies, and you can also (illegally) scrape it from there.
