For example:
World alienation, and not self-alienation, as Marx thought, has been the hallmark of the modern age. Expropriation, the deprivation of certain groups of their place in the world and their naked exposure to the exigencies of life, created both the original accumulation of wealth and the possibility of transforming this wealth into capital through labor. (The Human Condition, 254-5)I know from her letters to Jaspers that Arendt found Marx extremely frustrating ("a pain in the neck" are her words). Maybe it was the anxiety of influence...
UPDATE:
I guess Hanna Pitkin said much the same:
Although its [Arendt's criticism of Marx] overall thrust may well be valid and is surely defensible, its detailed formulations are almost always mistaken, sometimes blatantly so. Arendt’s account of Marx, moreover, leaves out about half of that admittedly inconsistent thinker, and what is missing from her Marx remarkably resembles Arendt’s own ideas in The Human Condition, particularly about the social.(The Attack of the Blob: Hannah Arendt’s Concept of the Social (Chicago, University of Chicago Press, 1998), p. 115.)