So, around $20 trillion worth (out of say $30 trillion) of hydrocarbons in the ground and on oil company books that can't be pumped and burned without trashing the global climate.
Not exactly fictitious capital, because maybe we will actually burn that stuff and trash the climate, but equally, maybe we'll somehow avoid doing that.
Sort of like Schrodinger's Cat
Not at all clear whether that's fictitious capital ('paper claims on wealth in excess of ... ' ... etc) or not. Question is still unresolved.
All capital is fictitious, in the sense that it doesn't, 'y'know, actually exist or anything. I'd call that a pretty good sense in which to be fictitious wouldn't you?
So what is capital then? It is a sign, or a system of signs. What we are calling the difference between 'fictitious' and 'non-fictitious' capital (as though there could ever be 'non-fictitious capital) is in reality the distinction between referential and non-referential signs.