  In this perspective, we introduce recent research into the structure and
function of complex investor networks supporting sustainability efforts. Using
the case of solar, wind and hydro energy technologies, this perspective
explores the complexity in low-carbon finance markets, defined as markets that
direct capital flows towards low-carbon technologies, using network approaches
to study their structure and dynamics. Investors are modeled as nodes which
form a network or higher-order network connected by edges representing projects
in which joint funding or security-related insurance was provided or other
investment-related interaction occurred. We review the literature on investor
networks generally, particularly in the case of complex networks, and address
areas where these ideas were applied in this emerging field. The complex
investor dynamics which emerge from the extant funding scenarios are not well
understood. These dynamics have the potential to result in interesting
non-linear behaviour, growth, and decline, which can be studied, explained and
controlled using the tools of network science.
