Introductory Context
"Quantitative Internal Bar Strength (IBS) mean-reversion strategy on Indian exchange-traded funds. Fading daily high-low range exhaustion for rapid overnight rebounds."
Internal Bar Strength (IBS): Exploiting Intraday Range Exhaustion
Internal Bar Strength (IBS), pioneered by quantitative researcher Sylvain Vervoort and formalized by Pagonidis, is one of the most robust short-horizon mean-reversion signals in quantitative finance. Rather than comparing today's close to past historical days, IBS measures where the current session's closing price finished relative to its own intraday high-low range.
The quantitative premise is straightforward: when an exchange-traded fund (ETF) or index finishes the session right at the absolute top of its daily range (IBS ≈ 1.0), market participants have reached peak short-term buying exhaustion, and prices tend to pull back into the next session. Conversely, an ETF closing at the absolute floor of its range (IBS ≈ 0.0) represents panic selling exhaustion, creating an attractive short-term overnight bounce opportunity.
• The Internal Bar Strength Formula
For ETF i on trading day t:
IBS_i = (Close_i - Low_i) / (High_i - Low_i) ∈ [0, 1]
Centered Score: Y_i = IBS_i - 0.5
When IBS = 1.0 (Close = High) → Rich / Short Signal. When IBS = 0.0 (Close = Low) → Cheap / Long Signal.
Cross-Sectional Dollar-Neutral Execution
Across the liquid Indian ETF and Sectoral Index suite, the strategy operates as a 1-day cross-sectional fade:
Buy ETFs that closed nearest their session lows (IBS ≤ 0.20). Captures the overnight and next-day mean-reversion bounce.
Short ETFs/Futures that closed nearest their session highs (IBS ≥ 0.80). Fades temporary intraday euphoria.
In a Long-Only retail framework, investors buy liquid ETFs (Nifty BeES, Bank BeES, Gold BeES) only on days when IBS < 0.20 and exit on the first day IBS > 0.80.
Execution Protocol & Edge Cases
Systematic implementation requires handling key market microstructure conditions:
- Zero Range Bars (High = Low): If an ETF experiences a trading halt or prints a zero range, the denominator is zero (IBS is undefined). The asset must be dropped from the day's rank; never impute IBS = 0.5.
- Delay-1 Next-Open Execution: The IBS score is calculated at 3:30 PM IST on official cash market closes. Fills are executed at the opening bell (9:15 AM IST) of the subsequent trading session.
- High Turnover: Because positions are rebalanced on 1-day holding horizons, turnover is close to 100% daily. Zero-brokerage accounts and low-cost execution are essential.
Failure Mode: Strong Trend Days (Continuation)
On powerful breakout trend days (e.g. Union Budget or macroeconomic rate cuts), multiple ETFs close at their highs together and continue surging higher for 2 to 3 consecutive sessions. Fading high IBS during strong trend regimes incurs direct sequential losses.
Educational and Research Content Only
This strategy documentation is for educational and quantitative research purposes only. Short-term mean-reversion involves execution slippage and market risk.