How do transition probabilities generate volatility persistence in a two-state market model?
Transition probabilities encode the likelihood of staying in or switching between states. In the two-state volatility example, high self-loop probabilities (0.8 for Low, 0.7 for High) mean the system tends to remain in its current state. This structure naturally generates persistence and clustering without adding manual rules.
Conditions
- The market is modeled as a two-state Markov chain.
- Self-transition probabilities are high relative to switching probabilities.
Reasoning, step by step
- Identify the two states: Low and High volatility.
- Read the self-loop probabilities: 0.8 for Low, 0.7 for High.
- Read the cross-transition probabilities: 0.2 for Low to High, 0.3 for High to Low.
- Interpret the large self-loops as the tendency for the current regime to persist.
- Conclude that persistence emerges directly from the transition structure.
Example
The diagram shows P(Low→Low)=0.8 and P(High→High)=0.7. The narrator explains that low volatility usually remains low and high volatility tends to persist.
Common misconceptions
- Believing that persistence must be added by hand as an extra rule.
- Assuming that switching probabilities are higher than staying probabilities in this example.
Watch the explanation
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