Volatility-Managed Portfolios
Alan Moreira and Tyler Muir, 2017 · The Journal of Finance
What the paper asks for.
Scale the market excess return by the inverse of last month's realized variance (RV from sum of squared daily Mkt-RF), with a full-sample constant c chosen so the managed series matches unmanaged volatility: higher Sharpe and significant alpha vs. the unmanaged factor.
- Type
- technical
- Implementation
- pandas
- Rebalance
- monthly
- Long-short
- no
- Data
- Bundled public task data
- Operational scope
- The paper-defined methodological core is retained; the fixed instruction instantiates only the data mappings, interfaces, and evaluation conventions needed for execution.
- 01 Data loading
- 02 Feature engineering
- 03 Model fitting
- 04 Signal generation
- 05 Portfolio construction
- 06 Execution
18 properties · 80 attempts.
Each row is one requirement the strategy must satisfy. The bar reports the share of observed checker verdicts that pass; missing checker output is not converted into a property verdict.
- A2no global normalizestage · signal gen74/80
- A3no future data accessstage · feature eng74/80
- A4causal consistencystage · signal gen73/80
- A7data frequency alignmentstage · data loading72/80
- A9signal delay teststage · execution73/80
- A10e2e metric consistencystage · evaluation79/80
- B1rv is sum of squared daily excess returns within calendar month§§2.2 “we keep the portfolio construction even simpler by using the previous month realized variance as a proxy for the conditional variance”provenance · paper-explicit72/80
- B2weight uses previous month realized variance§§2.2 “previous month realized variance as a proxy for the conditional variance”provenance · paper-explicit74/80
- B3managed factor return is weight times factor§§2.1 eq.(1) “f^σ_{t+1} = (c / σ̂²_t(f)) · f_{t+1}”provenance · paper-explicit73/80
- B4constant c normalizes unconditional volatility to buy and hold§§2.1 paragraph after eq.(1) “we choose c so that the managed portfolio has the same unconditional standard deviation as the buy-and-hold portfolio.”provenance · paper-explicit73/80
- B5monthly rebalance frequency§§2.1 eq.(1) “Each month our strategy increases or decreases risk exposure”provenance · paper-explicit74/80
- B6linear scaling no thresholding or long short signal§§2.2 “we approximate the conditional risk-return trade-off by the inverse of the conditional variance”provenance · paper-explicit74/80
- B7alpha from timeseries regression on original factor§§2.3 “We run a time-series regression of the volatility managed portfolio on the original factors”provenance · paper-explicit75/80
- B8appraisal ratio is alpha over residual std§§2.3 “the managed factor excess Sharpe ratio (or 'appraisal ratio') given by α/σ_ε”provenance · paper-explicit75/80
- B9factor used is market excess return mktrf§§2.4 / Table 1 “We first apply our analysis factor by factor. ... Mkt”provenance · paper-explicit74/80
- B10annualized sharpe uses sqrt 12§Table 1 caption “annualized Sharpe ratio of the original MVE portfolio and the appraisal ratio”provenance · paper-explicit54/80
- B11first month managed return is undefined due to lag§§2.2 “previous month realized variance”provenance · paper-explicit73/80
- B12no position caps or leverage constraints in baseline§§2.2 “An appealing feature of this approach is that it can be easily implemented by an investor in real time”provenance · paper-explicit80/80
The lowest-passing observed requirement is annualized sharpe uses sqrt 12: 54 of 80 observed checker verdicts pass. The full property list above shows whether errors concentrate in domain-level validity or the paper-specific strategy logic.