Margin Is Not a Footnote: Reg-T Feasibility as a First-Class Backtest Output
Collateral is a stochastic process separate from P&L, and can end a strategy independently of its returns.
A book that backtests well peaks at 151–154% of its own net liquidation value; peak-to-median requirement runs 6.7–16.1× across configurations.
A margined strategy’s collateral requirement is a separate stochastic process from its P&L, and it can terminate the strategy independently of the returns. Backtests that report only P&L cannot see this coming.
A far call wing costing about one-fifteenth of the equivalent put wing halves the book’s peak requirement, from 154% to 77%.
Reproducibility
The requirement-distribution exhibit regenerates from the published table
(python code/make_p5_figure.py). The underlying daily margin series derives
from licensed data and is not shipped.
Standing caveat
These are our Reg-T implementation’s numbers — hand-verified against published formulas and cross-checked between two independent builds, but not yet validated against broker-computed requirements. House minimums and add-ons can bind earlier.