Glossary term
Paper fill
Definition
A hypothetical journal line at a staged quote. No broker, no routing, no live order. Inherent limits: hindsight, no real fear, no taxes.
How it works
A paper fill is a journal line recording a hypothetical entry or exit at a staged quote. There is no broker, no routing and no live order; the product cannot send one. The note field is the point of the exercise: a fill with a written reason and a named friction teaches something, while ten silent lines are a spreadsheet game.
The record is optimistic in known directions. It is written with hindsight and without real fear, it fills at the price on screen instead of paying the spread, and it carries no taxes. A real round trip buys at the ask and sells at the bid, so a cost that scales with how often you act is missing from every paper line.
Worked example
Journal 100 units at a staged $50.00: a $5,000 hypothetical line. Journal an exit at $51.00 and the record shows +$100, or +2.0%. If a real round trip cost an assumed 0.10% in spread, $5,000 × 0.001 = $5 would come off a line the paper record shows as clean.
Frequency is where it adds up. At 0.10% per round trip, 60 round trips cost 6.0% a year, which would fully consume an assumed 6% gross edge. The paper record looks the same at 6 round trips and at 600. The course also shows that dropping some losing entries from the journal can fake a record: with 50 winners and 35 of 50 losers recorded, the win rate prints 58.8% from an edge of zero.
Hypothetical, for education only. Not a recommendation and not a prediction.
Common mistake
The mistake is presenting a paper blotter as proof of skill. It can show that a motion was practiced, and what reason you wrote at the time. It cannot establish an edge, a win rate or a return, because the record is subject to selection, friction it ignores and a steadiness real money would test. Hypothetical results should be labeled hypothetical every time they appear.