Adventure Consultants, formerly Hall and Ball Adventure Consultants, is a New Zealand-based adventure company that brings trekking and climbing groups to various locations. Founded by Rob Hall and Gary Ball in 1991, it is known for its pioneering role in the commercialisation of Mount Everest and the 1996 Mount Everest climb during which eight people died, including Hall, a guide, and two Adventure Consultant clients. Following the deaths of Ball and Hall, the company was purchased by Guy Cotter, who continued to operate the business.