Worked Examples

Berkshire Hathaway accumulated its Apple stake across 2016–2018 and trimmed it in 2020 — the lot list here is a split-adjusted reconstruction from its quarterly 13F holdings reports. Load it and watch the average cost settle at $36.73 while the sells realize billions without moving the average of what remains: the average-cost method at record scale. The $0.16 commissions and 12% illustrative tax rate are preserved from the original gallery.

GameStop closed at $17.25 on January 4, 2021 and at $347.51 on January 27 — the closing high the SEC staff report itself cites, on the way to an intraday $483 the next morning. One hundred shares, bought and sold at those closes, realize +$33,026 on $1,725 invested. The same report documents what surrounded those prices: trading restrictions, clearing-margin calls, and a market structure under stress.

Enron peaked at $90.75 in August 2000; by November 28, 2001 — days before its bankruptcy filing — it traded at $0.61. A hundred shares bought at the top show −99.33%, and the recovery arithmetic explains why that class of loss is terminal: getting back to even from −99.33% requires roughly +14,800%. The loss-recovery table on the break-even page is this story, tabulated.

Apple went public on December 12, 1980 at $22 a share. Five splits later (2:1 in 1987, 2000 and 2005, 7:1 in 2014, 4:1 in 2020) each IPO share had become 224 shares — so a hundred of them, about $2,200 at the offering, became 22,400 shares at a split-adjusted cost near $0.10. At $131.56, a mid-2021 price, the position values at roughly $2.9 million. The split factors are from Apple's own investor-relations FAQ.

The original gallery's dollar-cost-averaging scenario: about $5,000 into Tesla on the first trading day of every year from 2011 through 2023 — check any lot: 2,793 × $1.79 ≈ $5,000. The lots are split-adjusted, and Tesla split twice in the period (5-for-1 in August 2020, 3-for-1 in August 2022), which is why the earliest prices read as single digits. With 1% commissions on both sides and a 15% illustrative tax rate, it's the busiest realistic position in the gallery: watch the average climb as the buys walk up the chart.

Ten bitcoin at $999 in early 2017, all ten sold at $64,440 in November 2021 — the prices as captured in the original gallery. A fully closed position, so the entire result is realized P/L: +$634,410 on $9,990 invested, a return of +6,350.45%, with nothing left unrealized.

Berkshire's 2024 shareholder letter reports the famous table: per-share market value gained 5,502,284% overall from 1964 to 2024, compounding at 19.9% a year. Put $100 → $5,502,384 over 60 years into the CAGR calculator and the annualization falls out (19.95% before the letter's rounding) — six decades of a rate that sounds merely good producing a number that sounds impossible.

A textbook averaging sequence: 10 shares at $100, 10 more at $80, then 40 at $60 pull the average cost to exactly $70 — and take the capital at risk from $1,000 to $4,200 while doing it. With the price at $70 the position sits precisely at break-even, which is the whole seduction and the whole danger; the averaging-down article covers when this is a plan and when it is a bias.

The canonical position-sizing computation: a $10,000 account risking 1% has $100 to lose; an entry at $50 with a stop at $48 risks $2 per share; so the position is 50 shares costing $2,500. A quarter of the account deployed, exactly one percent of it at risk if the stop holds.

Ten thousand dollars into a 4%-yield position, dividends reinvested annually, with dividend and price both growing 5% a year. The year-by-year table shows the flywheel: payouts rise every single year even though the yield never changes, because the share count and the per-share dividend climb together.