Private equity-backed Siccar Point is seeking to sell up to half its stake in a major North Sea oil project led by Chevron, industry and banking sources said.

The value of Siccar Point’s 20% stake in the Rosebank project was unclear, since the project’s final scope and costs will only be determined once Chevron and its other partners, Suncor and Ineos, decide to go ahead with the development, the sources said.

Chevron began engineering studies for the project in 2012, but planning dragged out after oil prices collapsed in 2014 and the partners tried to reduce its costs.