Are shares fictitious capital?

The concept is 'introduced in chapter 25 of the 3rd volume of Capital, Fictitious capital contrasts with what Marx calls "real capital", which is capital actually invested in physical means of production and workers, and "money capital", which is actual funds being held. The market value of fictitious capital assets (such as stocks and securities) varies according to the expected return or yield of those assets in the future, which Marx felt was only indirectly related to the growth of real production."

Outside of Marx, is this concept developed elsewhere in economics? What are the critics of it?