Paper
Ghost protocols are the registry pages where both results and linked publications are absent. That is a different kind of silence than ordinary overdue results.
Which named CT.gov sponsors remain most ghosted once silence is narrowed from missing results to ghost protocols and read as excess over expectation? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot. Using the wave-nine sponsor watchlist, we ranked sponsors by excess ghost-protocol stock, raw ghost counts, black-box stock, and strict-core carryover. Cairo University carried the largest sponsor ghost excess at 228 studies, followed by Sanofi at 219 and Bayer at 179. Ain Shams University also remained prominent on ghost excess, while several of the biggest ghost repeaters were large industry sponsors with substantial black-box stock. The deeper-silence sponsor table therefore differs from the adjusted no-results table and pulls several ghost-heavy institutions to the front across universities, hospital systems, and major global drug-company portfolios all alike. Ghost-protocol status here is a registry-visibility definition based on missing results and missing linked publication references, not proof of total absence of reporting elsewhere.