Gartner is a US research and advisory company providing IT research, benchmarking and consulting to executives, known for the Magic Quadrant and Hype Cycle reports.
Forrester is a US research and advisory firm providing market research, analyst advice and consulting on technology, marketing and customer experience to business leaders.
KPMG is a Big Four network of member firms providing audit, tax and advisory services to businesses, governments and non-profits in more than 140 countries.