The eventual result was what chapter 8 calls a "superportfolio": a large, unstable structure of partially overlapping arbitrage positions. An event that was in itself less than cataclysmic the Russian government's default on its ruble-denominated bonds on August 17, 1998 caused that superportfolio to begin to unravel. Arbitrageurs who suffered losses in Russia had to begin selling other assets in the superportfolio; in an increasingly illiquid market, those sales caused prices to move sharply against the holders of the superportfolio, forcing further sales; and so on.

Donald MacKenzie, An Engine, Not a Camera, loc. 156