A Bubble Definition Based on Accelerating Price Growth

Summary

The document presents a technical definition of a financial bubble attributed to a research work on bubble mechanisms and diagnostics. In this account, prices during a bubble rise faster than an exponential growth path, sometimes displaying log-periodic oscillations. The phase is described as ending abruptly in a regime change, which may take the form of a crash or a substantial correction. The cited definition proposes that these distinctive patterns might allow bubbles to be identified before they end.

The author questions whether there is a single accepted meaning of “bubble” and asks for alternative definitions. No responses or empirical analysis are included, so the document does not compare competing definitions, establish how reliably the proposed patterns can be detected, or show that they provide useful advance warnings. The concept is best read as one specific diagnostic framing rather than a settled, universally agreed test. Its emphasis is on price dynamics and possible precursors to a sharp change in market regime.

Key ideas

• One proposed definition characterizes a bubble by price growth faster than an exponential path.
• Log-periodic oscillations may accompany this accelerating growth in the cited framework.
• The proposed bubble phase ends in an abrupt regime change, such as a crash or substantial correction.
• The document raises uncertainty about whether bubble terminology has a single accepted definition.

Tags

# Definitions of bubbles


# Definitions of bubbles












In Financial Bubbles: Mechanisms and Diagnostics, Sornette and Cauwels define the concept of "bubble":

More technically, during a bubble phase, the price follows a faster-than-exponential power law growth process, often accompanied by log-periodic oscillations. This dynamic ends abruptly in a change of regime that may be a crash or a substantial correction. Because they leave such specific traces, bubbles may be recognised in advance, that is, before they burst.

I'm not an expert in the field but it seems to me that "bubble" is something that anyone defines different. Do you know any other definitions of bubbles?

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.