Rocky Mountain Institute's (RMI) guide provides best practices for achieving zero over time for building portfolios. The authors are Matt Jungclaus, Alisa Petersen, and Cara Carmichael. Billy Grayson, Monika Henn, and Urban Land Institute are also contributing to the report. The guide was edited by Cindie Baker, edited by Laurie Guevara-Stone, and designed by Romy Purshouse. The authors would like to thank the generous support and collaboration from Blair Madden Bui, CEO of the John Madden Company, and the individuals who shared their wisdom and expertise. The guide covers various topics such as financing, design, and operations. The authors are grateful to the following individuals: Blair Bui, John Madden Company; Andy Bush, Morgan Creek Ventures; Michael Chang, Host Hotels and Resorts; Ian Clampert, Vail Resorts; Jonathan Flaherty, Tishman Speyer; Greg Hopkins, Rocky Mountain Institute; John Lower, John Madden Company; Jamie Mandel, Rocky Mountain Institute; Sara Neff, Kilroy Realty Corporation; Victor Olgyay, Rocky Mountain Institute; Dave Pogue, CBRE; Phillip Saieg, McKinstry; Will Teichman, Kimco Realty Corporation; and Kelly Vaughn, Rocky Mountain Institute.