Shu Yu and Mulvey 2024

A study by Yizhan Shu, Chenyu Yu and John M. Mulvey (Princeton University, ORFE), published in the Journal of Asset Management in 2024 (preprint arXiv:2402.05272; the preprint was retitled from “Regime-Aware Asset Allocation” to “Downside Risk Reduction Using Regime-Switching Signals” on the way to publication). It compares regime-identification models for a “0/1” stock-versus-cash equity-timing strategy on the S&P 500, DAX and Nikkei 225 over 1990-2023, with a conservative 10bp one-way transaction cost and trading-delay robustness checks of 1, 5 and 10 days. It benchmarks a two-state Gaussian hidden Markov model against the Statistical Jump Model.

The headline result is that the JM-guided strategy beat the HMM-guided strategy on every index — S&P 500 return 11.2% vs 8.5% (Sharpe 0.68 vs 0.54), DAX 8.6% vs 6.4%, Nikkei 4.7% vs 2.5% — and cut maximum drawdown below both the HMM and buy-and-hold (e.g. S&P 500 -26.6% vs the index’s -55.2%). The mechanism is turnover: the JM’s persistent regimes produced turnover of just 44-72% against the HMM’s 141-290%, and that churn is what eroded the HMM’s net edge. Read honestly, this makes the JM a superior risk filter, not a large alpha source: the JM’s return advantage over buy-and-hold is modest on the S&P 500 and comes mainly from drawdown control on the DAX and Nikkei. The paper appears in this vault as the primary trading-relevant evidence that all regime models suffer detection latency — a ~25-day median lag in detecting turning points; during the COVID-19 crash the online signal lagged the onset and end by roughly half a month, missing the rebound but avoiding a ~20% drawdown.

Two caveats temper the result. The jump penalty was tuned by time-series cross-validation to maximise the very 0/1 strategy being evaluated, so the JM-vs-HMM margin is partly a design choice rather than clean out-of-sample alpha. And the JM-beats-HMM trading result rests on this single research group; no fully independent replication with costs exists. The strategy does, however, clear genuine out-of-sample testing with realistic costs, a benchmark and drawdown metrics — hence a moderate profitability grade.

Shu Yu and Mulvey 2024 [reports_profitability] Statistical Jump Model Shu Yu and Mulvey 2024 [reports_underperformance] Hidden Markov Model Regime Detection Shu Yu and Mulvey 2024 [includes_costs] Transaction Costs and Slippage

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