RWE aims to sell a minority stake in British offshore wind farm Humber Gateway, as the German utility seeks to release cash for expansion in renewable energy.
Morgan Stanley plans to launch the deal, which could value the asset at more than 1.2 billion euros.
Infrastructure and pension funds as well as insurers were expected to show interest, they added.
RWE and Morgan Stanley declined to comment.
Utilities, including RWE, are investing in renewable assets to reduce their carbon footprint, but they often bring in minority investors for wind farms once they are operating to allow them to focus on new projects.