[dragonwriter]

Terminologically, both the middle and upper classes in the Marxist framework are bourgeois, the middle (mixed capital/labor dependent )being the petit bourgeoisie and the upper (pure capital dependent) being the haut bourgeoisie.

[OkayPhysicist]

While true, in Marx's time there wasn't nearly the level of mass involvement in capital investment as there is today. When Marx talks about the petite bourgeoisie, he's talking about shopkeepers who own their shops, farmers who own their farms, etc.

The guy who works a 9-5 but invests some of their paycheck in publicly traded stocks has a lot more class interest in common with all the other wage workers than they do with a small business owner.

[dragonwriter]

> The guy who works a 9-5 but invests some of their paycheck in publicly traded stocks has a lot more class interest in common with all the other wage workers than they do with a small business owner.

Sure, and they'd still be proletarians, even if, in many cases -- and this will often be characterized as "middle class" or even "upper middle class" depending largely on income in American discussions -- part of the proletarian intelligentsia. There's also a wider array, now -- though its still a small share of the population -- of patterns of economic participation that involve loosely balanced (in the sense that both are important, if not equal, contributors) labor (either wage-labor for another or labor applied to your own capital in one way or another) and capital dependence, and which are still petit bourgeois, and which is still the distinct middle class between the proletarian and the haut bourgeois, not the false middle-income workers "middle class" invented to divide the class dependent on wage-labor.