Research Notes

Notes from the quant lab.

Short, opinionated notes on factor judgment, risk design, and numerical methods: the discipline behind the dashboards.

From factor idea to verdict

Distribution checks. Concentration checks. Rank tests. Portfolio tests.

  • Start with the cross-section. A factor with a broken or wildly skewed distribution needs different treatment before it becomes portfolio logic.
  • Inspect concentration. Sector, industry, and market-cap breakdowns reveal whether the factor actually measures the economic intuition it claims to.
  • Measure rank quality. IC, Spearman correlation, monotonicity, and the top-minus-bottom spread tell a richer story than a single return number.
  • Backtest buckets and the portfolio. Quintiles and deciles show whether the signal degrades smoothly or only works at the extremes.
  • End with a verdict. Users need to know whether the factor is promising, weak, noisy, sector-biased, or only conditionally useful.

Sector composition is not a footnote

Signal or sector bet. Separate them before trusting the spread.

  • Sector composition by quintile shows whether the top bucket is diversified or simply overexposed to one economic theme.
  • Median factor values by sector help separate stock-level signal from industry structure.
  • Industry-level breakdowns catch hidden clusters that broad sector labels can smooth over.
  • A benchmark line or universe median gives users an anchor for judging whether a bar is extreme.

Numerical methods as product design

Method choice → visible risk surface.

  • Lattices work well when early exercise matters and you want the decision tree visible.
  • Least Squares Monte Carlo is strongest when the exercise policy has to be estimated from simulated paths.
  • Finite difference methods make value surfaces and Greeks easier to inspect across the grid.
  • Variance reduction is not cosmetic. It can determine whether a Monte Carlo estimate is usable in an interactive workflow.
  • For securitized products, rate scenarios and embedded optionality need to be reviewable side by side.