The following is a lucidly written essay by Nitzan and Bichler on the evolution of the terms "imperialism" and "financialism" among Marxists:
It's a 13-page printout and I've never seen the terms so clearly discussed. Like many people, I grew up with Baran and Sweeezy's "Monopoly Capital"; and like many others I've read Foster and Magdoff's recent "The Great Financial Crisis." But I've been blissfully ignorant of how the discussion among Marxists has gradually shifted over the decades -- partly because the same terms are used.
Nitzan and Bichler are famous for their 2002 book, "The Global Political Economy of Israel," which perhaps Mayday Books had in stock some years back.