Definition
Regime Filter
A regime filter is a rule that switches a strategy on or off, or adjusts its risk, based on detected market conditions such as volatility level, trend or liquidity, to avoid trading in unfavourable environments.
Indian trend and mean-reversion strategies often degrade in the wrong regime: mean reversion suffers in strong trends, and trend following bleeds in choppy markets. A regime filter, for example a volatility or trend strength gauge, scales exposure down or pauses the strategy when conditions are hostile.
Well-designed regime filters improve risk-adjusted returns, but poorly designed ones add parameters and invite overfitting. The art is to use robust, economically sensible regime indicators that generalise out-of-sample rather than ones tuned to fit historical drawdowns perfectly.
Related terms
- Mean Reversion StrategyA mean reversion strategy assumes that prices or spreads that deviate from a historical average will tend to return to it, so it sells what has risen sharply and buys what has fallen.
- Trend FollowingTrend following is a strategy that buys assets whose prices are rising and sells or shorts those that are falling, on the premise that established trends tend to persist for some time.
- OverfittingOverfitting, or curve-fitting, occurs when a strategy is tuned so closely to historical data that it captures random noise rather than a genuine pattern, and consequently fails on new data.
- Maximum DrawdownMaximum drawdown is the largest peak-to-trough decline in the value of a portfolio or strategy over a period, measuring the worst loss an investor would have suffered before a new high was reached.
Plain-English explainer from The Dispatch Investors Encyclopedia. General information, not financial advice.