Methodology
A price guide is only as honest as its worst shortcut. Here is exactly how every number on this site is built — and what it can't tell you.
Source
Completed (sold) eBay listings, pulled daily for each of the 132 cataloged models. eBay exposes roughly the trailing 90 days of sold results, so every figure is a ~90-day window — long enough to smooth week-to-week noise on most models, short enough to track a moving market. Each model page shows its as-of date.
Filtering
Raw sold results are noisy, so each listing must pass three gates before it counts as a comp:
- Model match. The listing title must contain the maker and the model's identifying tokens (with known aliases — "PFM" and "Pen For Men" both count; "Vacumatic" and "Vac" both count).
- Accessory rejection. Nib units, converters, empty boxes, ink, cases, parts/repair pens, pencils and ballpoint/rollerball siblings are rejected by pattern — a comp has to be the pen itself.
- Price floor. Each model carries a floor below which listings are excluded as accessory noise (a $30 "Montblanc 149" is a box or a nib, not a 149).
The math
Surviving comps are IQR-trimmed (values beyond 1.5× the interquartile range are dropped) and we publish the median, plus the trimmed range and sample size. Medians resist the mislabeled bundle and the fantasy sale; the sample size tells you how much to trust the number.
What we can't see
- Condition, nib and originality. A wet-noodle flex nib or first-year production can double a price; a cracked cap can halve it. Titles rarely say. Medians are market context, not appraisals.
- Best-offer amounts. eBay shows the listed price for accepted offers, not the (lower) accepted amount — sold figures skew slightly high on models where offers are common.
- Off-eBay sales. Pen shows, auction houses and forum sales aren't in the data. For most models eBay is the deepest liquid market; for top grails, auction results can run higher.
- Fakes. We reject obvious accessory listings but can't authenticate pens. High-fake models (Montblanc above all) deserve extra care.
Rarely-traded models
Some cataloged grails legitimately sell a handful of times a year. When a window has no qualifying sales we say "rarely traded" rather than inventing a number — and members can set an alert for the day the next real sale lands.