Capitalism

A version of the Doctor from an Alternate universe described capitalism in the following way; "Some people win; most lose all they had.", (AUDIO: The Emporium At The End) although there was disagreement as to whether or not this descriptor was also fairly applicable to the version of Captalism in operation in N-Space, as well, with various incarnations of the "prime" Doctor displaying different opinions on this; with, for instance, the Twelfth Doctor (TV: Oxygen) expressing a similarly negative analysis, but the Third having more mixed views, believing unemployment to be "Capitalism’s biggest problem", but admitting to the President that he "seem[ed] to have fixed" that. (AUDIO: The Paradise of Death).

Capitalism was sometimes juxtaposed with Feudalism (TV: The Monster of Peladon), or Communism (AUDIO: Brotherhood of the Daleks).

Capitalism could be exploited to the extreme with no regard to the lives of others. Ganymede Systems began to not providing oxygen in space stations and forced people to buy it via smart suits. They also began killing workers when they hadn't been productive enough and brought into new workers. However, thanks to the Twelfth Doctor, a rebellion was started and Ganymede Systems was overthrown. According to the Doctor, the incident "about wrap[ped] it up for capitalism." but clarified its end only led to humanity making "a new mistake" (TV: Oxygen).

The Eighth Doctor was assumed to be a capitalist by several people in Spain. Fitz Kreiner branded Anji Kapoor a "capitalist pig" who was in turn surprised by how similar career communists and career capitalists were.

While fighting in the Spanish Civil War, Bob Edwards used a megaphone to shout out lengthy political arguments about the capitalist system. (PROSE: History 101)

Behind the scenes
In real life, Capitalism is the global economic system following Feudalism. It has been defined in various ways, with wage labour, commodity production for profit, private ownership of the means of production, voluntary exchange, competitive markets, and many more, all being suggested by various sources as "a defining feature". However, no attempt at any sort of definition, whether mainstream, libertarian, Marxist, or of any other nature, has been made in the series, meaning this page can only include examples that specifically use the word capitalism. This means that stories such PROSE: Closing the Account, featuring the Doctor meeting Stalin and implying that Capitalism will be overthrown some unspecified time in humanity’s future, and TV: Kerblam! featuring a line about how "the problem isn’t the System", (referring in-universe to an AI program literally called "the System", albeit with an obvious metatextual implication) cannot be mentioned in the in-universe portion of the page.