cockroach effect n.— «It’s sort of like what they call the “cockroach effect” on the financial markets. Every time there’s “hints” of anything going wrong inside a company, everybody starts selling the company’s stock in a knee-jerk vote...
death cross n. in financial markets, a situation where long-term and short-term averages converge, seen as evidence that values will decline. (source: Double-Tongued Dictionary)