Methodology

Daily time-weighted return, r = (V_end − F) / V_start − 1, linked geometrically. V is total account value at the close; F is the day's external flow. Flows earn no return on the day they arrive.

Through 2026-09-25, daily values are rebuilt from the account's transaction history and statement flows. After that, each day's value comes from the manually maintained holdings, reconciled weekly to the broker, priced at the official close.

SPY: SPDR S&P 500 ETF (SPY), total return from dividend- and split-adjusted closes. Replaced the S&P 500 Total Return index (^SP500TR) on Oct 16, 2026, so both benchmarks use the same adjusted-close basis.

QQQ: Invesco QQQ Trust, total return from dividend- and split-adjusted closes, used as a proxy for the Nasdaq-100. It is not the official Nasdaq-100 Total Return index.

Statement-reconciled monthly cross-check: Aug 2025 to Jun 2026, Modified Dietz +33.90%; daily series +34.02%. Monthly Modified Dietz returns from month-end statement values and dated statement flows, linked over the same months. The small remaining gap comes from Dietz approximating when flows arrive within each month; the daily series measures it directly.

Sample standard deviation of monthly returns (daily returns compounded into complete calendar months), annualized by the square root of 12. Descriptive, not a forecast. Monthly frequency, complete months only, July 2025 counted from inception on July 3. Risk-free rate 4% a year. Sharpe standard error uses the iid approximation √((1 + ½·SR²)/n), annualized; the 95% interval is ±1.96 standard errors. With this few months, the interval is wide and the point estimate is not reliable. Maximum drawdown is measured on daily values; beta from daily returns against SPY.

Holding-level contribution to portfolio return is not calculated. Attribution would require valuation at every execution, which this book's frequent partial exits and re-entries make unreliable, so it is left out rather than estimated.

Figures are calculated from unrounded values and shown to two decimals. Monthly returns link to the cumulative figure before rounding, so a total built from rounded parts can differ slightly.

Performance

Prices come from Yahoo Finance and are delayed. The site uses four separate labels for the day's data:

Holdings snapshot

The date the published weights describe. It changes only when a new snapshot is recorded.

Intraday estimate

The portfolio's move during the session from delayed quotes. It never enters the official series.

Preliminary closing return

Written at 16:15 ET from the last trade.

Final closing return

Rewritten that evening from final closing prices.

A holding's price change is its own move from delayed quotes. It is not its contribution to the portfolio's return. A page notes when quotes have not updated for more than two hours during market hours.

Weights are shares of securities, so cash is excluded. They are maintained by hand from the broker's positions and reconciled to the account total at least weekly, and they are rounded to two decimals, so they may not sum to exactly 100%.

Portfolio

Each row is one period of ownership that has ended, from first purchase to the sale that closed it. Return is realized on the shares sold: proceeds plus dividends, less purchase cost and fees, over that cost. It is a different measure from the portfolio's time-weighted return, and periods are not weighted by size. Exits after the transaction history used for these calculations are listed as pending rather than estimated.

Closed ownership episodes

The date a rationale was first recorded is the date of the first commit in the site's version history that contains its wording. A rationale first recorded more than 14 days after the trade is labelled as recorded later.

Weights are shares of securities around each trade, where they could be reconstructed. Where only the month of a trade is known, the entry says so and no day is shown, and the timing of its rationale is marked as not confirmed. Trades without a surviving rationale say so; none has been written after the fact.

Decision log

First published is the date of the first commit that added the thesis. Last revised is the date of the latest commit that changed its text. Both come from the site's version history; a revision can be a small edit and is not a full review.

“Last revised” is a change to the text, not a formal review of the thesis; no thesis has a recorded review date. Financial figures on thesis pages come from company filings with the SEC, and margins and growth rates are calculated from those figures; each chart says which. A paper's date is its publication date.

Research