Intraday Equity Sampling: Audit Short-Hold Risk

Intraday equity sampling: Keep marked equity observations close enough to the holding horizon to reveal sampled underwater periods.

Intraday equity sampling matters even when positions are held briefly. A short holding period is a duration measurement, not a maximum-loss guarantee. Day-end equity can miss an observed intraday peak or trough, while a position-allocation percentage describes notional exposure rather than the loss that an exit can reliably enforce.

The Reddit discussion contrasted intraday and closing losses. Author results remain unverified, and some replies were inaccessible. All account values below are original synthetic examples, not reproduced brokerage records.

Intraday equity sampling: keep four quantities separate

Record account equity, gross position notional, intended risk under the strategy's assumed exit, and observed marked loss. A $4,000 position in a $10,000 account is 40% notional allocation. An intended 1% position stop corresponds to $40 before modeled costs only if the assumed fill occurs. It does not establish a $40 maximum loss under gaps, failed delivery, or insufficient liquidity.

SEC order guidance distinguishes stop and market behavior. Your risk report must retain its execution assumptions. Do not label intended stop exposure as realized or guaranteed account risk. Include open-position marking rules and any leverage or contract multiplier explicitly.

A synthetic sampling comparison

Imagine equity begins at $10,000, reaches $10,500 at noon, drops to $9,450 later, and closes at $10,100. Relative to the observed noon peak, the decline is 10%. A dataset containing only the opening and closing marks shows a gain and omits that peak-to-trough episode.

This example does not mean every daily dataset understates risk by a predictable amount. It means the metric is conditional on observed marks. More frequent observations can reveal additional excursions, but missing quotes, stale valuations, and different mark conventions can still obscure the account path. Never manufacture intraday peaks from daily closes.

Define the equity capture contract

For every mark save event time, availability time, cash, positions, valuation prices, price ages, fees, and any external cash flow. State whether equity uses midpoint, bid/ask liquidation estimates, last trades, or broker-reported values. Those are distinct valuation contracts. Retain stale or incomplete statuses instead of presenting uncertain marks as fresh observations.

Capture restarts and disconnects as gaps. A missing hour is not proof that equity stayed constant. If an account receives a deposit, isolate that cash flow from strategy return before calculating peaks. Preserve the raw marks alongside any derived, cash-flow-adjusted series.

Compare like-for-like paths

First calculate drawdown on the same marked basis at the original cadence. Then downsample that very path to the daily rule you want to inspect. This paired exercise isolates sampling loss more cleanly than comparing two providers with different prices, cash histories, or fee accounting. Keep observed intraday depth, closing depth, and the unavailable intervals visible together.

Find the offline input guide through Tradewink Advisory Research. Start with the four synthetic marks and confirm the 10% observed decline before loading account data. The result is an advisory measurement of the supplied path. It does not predict future losses, establish capital adequacy, or authorize a new live equity stop.

Continue the research

Trading Research Costs: Build a Vendor Budget and Trading Strategy Provenance: Audit Imported Winners develop adjacent checks. Use a small synthetic fixture first; these educational diagnostics do not validate a trading edge or change account settings.