Refers to something being planned, especially within companies or organizations.

Future Projects

Projects 'on the stocks' may be secret until public announcements are made.

Confidential Plans

Suggests projects are not yet active or visible to outsiders.

Originally refers to shipbuilding, with 'stocks' being the frame used to support a ship under construction.

Highlights that something, typically a structure or machine, is currently being built.

Can be used figuratively to indicate any large projects that are in development.