HolderBook

What this site checks about itself

Every night, after the filings are loaded, these figures are recorded and compared against the night before. They are published because a site that reports its own error rate is easier to trust than one that asks you to assume it has none.

21
Figures watched
0
Moved a lot since last night
1
Moved a little
2026-09-16
Last checked

Why movement rather than a target. We do not know the correct value for most of these numbers, and a threshold invented for the purpose would either cry wolf or stay silent. What we do know is that they should not change much between one night and the next. A figure that jumps is worth looking at whatever its level, and that is what this page reports.

Nothing here stops the site publishing. A number moving is a reason to investigate, not a reason to withhold the data, and a check that could break the site would be switched off the first time it was wrong.

What is measuredLatest ChangeReading
Institutional value, latest quarter
as at 2026-06-30
84,193,491,109,300+0.0%Steady
Filers in the latest quarter
2026-06-30
8,863+0.0%Steady
Securities with a ticker
2026-06-30
13,860+0.1%Steady
Largest single position
one manager, one security
407,198,013,000+0.0%Steady
Positions whose share count is disputed
implied price contradicts the market
3,633+12.7%Steady
Securities we cannot price
no cross-filer price
315+6.4%Steady
Funds with a measured return
2026-06-30
8,087+0.0%Steady
Average disclosed book return
percent, outliers excluded
12.54+0.0%Steady
Largest single quarterly return
percent. A number in the thousands is a bug, not a manager
241.54+0.0%Steady
Insider transactions held
rolling year
418,196+0.3%Steady
Insider values we could not trust
filer figures that contradict the market or themselves
3,875+0.0%Steady
Option lines carrying no value
correct: an option's value divided by its shares is not a price
110,779+0.2%Steady
Open market purchases, last 180 days
dollars. Officers and 10% owners together
17,998,942,442+0.1%Steady
Insider trades dated in the future
a filer mistyping the year
11+0.0%Steady
Insider trades dated before 1990
the same mistake in the other direction
0-Steady
Form 4 filings that would not parse
should stay near zero
6+0.0%Steady
8-K filings held2,589+9.1%Steady
8-K item titles not in the lookup
a new or reworded item shows up here
2+0.0%Steady
Tender and going-private filings held125+8.7%Steady
Tender filings with a price
most are fund repurchases with no fixed price
12+9.1%Steady
Activist events detected221+1.8%Moved

What has actually gone wrong

These are real faults found on this site, all of them silent: nothing crashed, and every one was found by somebody reading output that looked odd. They are listed because they are the reason this page exists.

Each was fixed when found. The point of publishing them is that the next one is easier to see.

Compared against the run at 2026-09-15T13:23:00Z. The underlying figures are recorded each night and kept, so a slow drift shows up as well as a sudden jump.