Executive SummaryIn this exploratory paper, we examine real estate managerial decisions; specifically, who is responsible in large real estate investment management for sustaining sustainability at the firm and asset operational level. These decisions are distinct from the acquisition of sustainable buildings. We employ 93 semi-structured interviews conducted with professionals at direct lenders, executive search firms, life insurance companies, owner-operators, private equity funds, publicly-traded REITs, third-party real estate service firms, and tax credit syndicators. Results indicate five unique approaches to sustaining sustainability at the asset and firm level: corporate, property manager, asset manager, and consultant driven, as well as stand-alone strategies. Further, interviewees suggest that the value proposition of sustainability initiatives can be enhanced through management collaboration to leverage unique data streams.