CT.gov Sponsor Backlog Concentration
2026-03-29 | full-registry ct.gov audit | plots, figures, and e156 bundle
Series
IndustrySponsor ClassesPhasesStructuralVisibilityCohortsConditionsConcentration
Concentration Dashboard

A relatively thin sponsor slice carries most of the CT.gov missing-results backlog

The missing-results backlog spans many sponsors, but the stock is highly concentrated once ranked by sponsor volume.

Open dashboardRead E156 paperProtocolSeries hub
Concentration shares
Top sponsors
Ghost sponsors
Inequality

Dashboard

Open dashboard at rootRead E156 micro-paperOpen protocolOpen series hub

Concentration metrics matter because a diffuse-looking registry can still be dominated by a relatively small sponsor slice.

How to read the dashboard
Lead sponsors
25,584
Eligible older backlog
Top 1% share
39.6%
Missing-results stock
Top 100 share
25.7%
Missing-results stock
Top 500 share
51.1%
Missing-results stock
Concentration shares
CONCENTRATION SHARESShare of the missing-results backlog held by selected sponsor slicesTop 1% sponsors39.6%Top 5% sponsors67.0%Top 10% sponsors77.4%Top 20 sponsors9.0%Top 100 sponsors25.7%Top 500 sponsors51.1%
Top sponsor slices accumulate backlog very quickly, especially once the view shifts from 1 percent to 10 percent.
The point of this chart is not that the tail is small. It is that the head is disproportionately large.
Top sponsors by stock
LARGEST SPONSOR STOCKSLead sponsors with the biggest absolute missing-results backlogsGlaxoSmithKline1,246Assistance Publique - Hôpitaux de Paris1,121Cairo University1,065Mayo Clinic1,022National Cancer Institute (NCI)963AstraZeneca864Riphah International University864Boehringer Ingelheim856Sanofi852Pfizer837
Large pharmaceutical firms, universities, and public institutions appear together near the top of the stock ranking.
Concentration is not confined to a single sponsor class, which is why the top-sponsor view matters alongside the sponsor-class projects.
Top sponsors by ghost stock
LARGEST GHOST STOCKSLead sponsors with the biggest no-results plus no-publication stocksGlaxoSmithKline815Boehringer Ingelheim799Mayo Clinic776Cairo University739National Cancer Institute (NCI)713Pfizer676AstraZeneca643M.D. Anderson Cancer Center587Sanofi582Novartis Pharmaceuticals521
The ghost-stock ranking overlaps with the stock chart but also highlights sponsors whose records remain hidden on both main visibility channels.
Ghost stock is the more stringent backlog definition because it removes publication-only cases from the numerator.
Read Across Projects

Across The Series

Each project isolates a different dimension of registry opacity, but the point is the contrast between them, not a single leaderboard.

Industry
CT.gov Industry Disclosure Gap

Industry-focused missing-results stock, sponsor backlogs, and structural sparsity inside CT.gov.

Sponsor Classes
CT.gov Sponsor-Class Hiddenness

Sponsor-class comparisons on rate, stock, and structural hiddenness rather than one flattened ranking.

Phases
CT.gov Phase Reporting Gap

Phase-by-phase disclosure gaps showing how silence changes along the development pathway.

Structural
CT.gov Structural Missingness

Field-level missingness across publication links, IPD statements, descriptions, and locations.

Visibility
CT.gov Evidence Visibility Gap

Results-plus-publication visibility states showing how many older trials are fully visible, partly visible, or ghosted.

Cohorts
CT.gov Completion Cohort Debt

Completion-era reporting debt showing how older eligible cohorts drift on no-results and ghost-protocol rates.

Conditions
CT.gov Condition Hiddenness Map

Keyword-classified therapeutic-area hiddenness mapping across common condition families.

Source on GitHub | Project home | Dashboard