1. Gartner is known for its huge influence on purchasing as well as an unequaled events business.
2. Forrester Research benefits from Gartner's weaknesses. Clients rate its peer communities most highly, and its reprints business is clearly a threat to Gartner.
3. HfS Research pipped IDC into third place, despite having a more uneven portfolio of services and a far smaller client base. Even so, the firm's exceptionally wide freemium base means that it is delivering highly valuable services to a wide number of users.
4. IDC's base of paying customers means it doesn't have to panic. Users in the Americas rate its research even more highly than Forrester's, and its reprints business extends its audience.
5. Digital Clarity Group rounds out the top five. DCG's is highly rated for its advisory services and influence on purchasing.
6. NelsonHall is rated highly for research and, even more so, for its inquiry calls. It is held back by its limited ability to deliver business leads.
7. ISG, unlike NelsonHall, is very highly rated for business leads. The firm offers strong advisory and inquiry services, but is held back by weak peer networking. Its purchase of Saugatuck might help.
8. Everest Group is once more highly rated for research and for reprint rights, but is held back by its lack of a major investment in events.
9. KPMG, which acquired sourcing advisors EquaTerra, is a new entrant in the top ten. That reflects the broader range of services being used to consume analyst insight. Despite lacking a serious research program, KPMG seems to be effectively competing in the market for analyst-level advisory services and purchasing guidance.
10. CEB, which includes TowerGroup, has a unique business model. Its peer communities are its most highly valued service, but its seems to have little impact on purchasing.

转自：https://www.linkedin.com/pulse/gartner-forrester-hfs-idc-top-2016-americas-analyst-firm-chapple