The Impact of Trump-Era Tariffs on Financial Market Efficiency

Battle Count: 78

The paper provides valuable insights into how market efficiency (measured via Hurst exponent and multifractality) changes under geopolitical shocks like tariffs. This is directly relevant for quantitative traders who need to understand regime changes in market predictability. The finding that Trump tariffs have moderate but observable effects on efficiency across all assets suggests that tariff events create temporary inefficiencies that could be exploited. The rough volatility framework connection (VIX anti-persistence) is relevant for volatility-based strategies. However, the paper is primarily descriptive/analytical rather than prescriptive, and does not propose specific trading strategies or backtest results.

MFDFA is a well-established algorithm with clear procedural steps (profile construction, segmentation, polynomial detrending, fluctuation function computation, scaling analysis). The rolling window approach adds moderate complexity. The main implementation challenges include: (1) proper handling of the forward/backward segmentation, (2) choosing appropriate polynomial order for detrending, (3) estimating h(q) reliably across the q range, (4) computing the Legendre transform for the singularity spectrum, and (5) managing the rolling window computation efficiently. Open-source MFDFA implementations exist in Python and MATLAB, reducing practical complexity. The analysis of six assets across two data types (returns and absolute returns) increases computational load but not algorithmic complexity.

The MFDFA methodology is well-described with explicit equations (Steps i-v). Data source (investing.com) and time period (Jan 2014 - Sep 2025) are specified. However, no code repository is provided, and the specific implementation details (e.g., exact segment sizes, polynomial fitting procedure) would need to be reconstructed. The rolling window parameters (750 trading days for most assets, 365 for BTC/USD) are clearly stated. Results are presented only in figures, making exact numerical reproduction difficult.