Herd Mentality
The tendency for investors to follow the crowd rather than conduct independent analysis, amplifying market trends and bubbles.
What is Herd Mentality?
Herd mentality in investing describes the tendency to mimic the buying and selling behavior of the broader crowd, assuming that the collective action of others reflects superior information or judgment. Herding amplifies market trends — turning momentum into bubbles during upswings and panic into crashes during downturns. Rational reasons for herding include career risk (fund managers underperform if they differ from peers) and information cascades (sequential decisions where each actor rationally follows prior actors). Contrarian investors attempt to profit by trading against herd behavior at extremes.
Example
During the dot-com bubble (1995–2000), investors poured capital into internet companies with no profits or clear business models because others were doing so. The Nasdaq Composite rose 400% before collapsing 78% from peak to trough. More recently, meme stocks like GameStop in 2021 demonstrated retail herd behavior, with prices detaching entirely from fundamental value as crowds followed social media momentum.
Source: Investopedia — Herd Mentality